APPENDIX to THIRD REPORT OF THE COMMISSIONERS appointed to inquire into the 



A.Reports prepared for and presented to the Commissioners on specified Heads of Inquiry:-

Nature, Propagation, Progress, and Symptoms of the Disease; J. B. Sanderson, Esq., M. D. (Click Here)  


Chemical Pathology of the Disease; W. Marcet, Esq., M. D.


General Pathology of the Disease, and its relation to Human Diseases; C. Murchison, Esq., M. D.            


Morbid Anatomy of the Disease; J. S. Bristowe, Esq., M.D.     


Microscopical Researches on the Disease; Lionel S. Beale, Esq., M. D. (Click Here)


Disinfection and Ventilation; R. Angus Smith, Esq., Ph.D.


Application of Disinfectants in arresting the spread of Cattle Plague; William Crookes, Esq., F. R. S. (Click Here)


Treatment of the Disease; George Varnell, Esq., M. R. C. V. S., and William Pritchard, Esq., M. R. C. V. S.           


Report to Her Majesty's Commissioners on the Treatment of the Disease, and its extension to Sheep, by the Edinburgh Cattle Plague Committee.    


Nature, Propagation, Progress, and Symptoms of the Disease




John Burdon Sanderson (1829-1905) Photo with copyright permission of Welcome Institute Library, London  V28386

Photograph, with copyright permission from Wellcome Library, London. 

[Excerpts from Reports prepared for and presented to the Commissioners on specified Heads of Inquiry]

Part I [Omitted]

Part II. 


    Of the numerous and complicated questions relating to the propagation of Cattle Plague which were included in the plan of the present inquiry as originally laid down, I have been able to investigate experimentally, those only which refer to the nature and properties of the contagious principle of the disease as they are exhibited in the effects of inoculation, and to the length of the period of incubation.


1. Effects of inoculation.


The question which stands first in its practical bearing on the employment of inoculation as a means of eradicating or preventing Cattle Plague is the following: - Is it possible by inoculation to produce a form of disease which, while it is protective against future attacks, is yet so mild that it admits of certain cure under ordinary circumstances, or in other words, that the affected animals, as a rule, recover with reasonable care as to hygienic conditions ?

This question does not at present admit of an answer. It is true that although the results of the countless inoculations of Cattle Plague, which have been performed since the practice was first introduced in 1754,* {Of these an excellent account is given in Prof. Unterberger's “Beitrage zur Geschichte der Rinderpestimpfung.” Dorpat, 1865.} show that there is no appreciable difference either as regards symptoms, progress, or duration, between the disease produced by inoculation and that which results from natural infection, provided that two fatal cases, or two cases of equal severity are compared with each other, yet the proportion of fatal and severe cases is much smaller in inoculated animals than in those naturally infected. So much so that in the majority of the former the malady is deprived of its malignant character, and tends to spontaneous recovery. 

But this fact loses its practical value by its inconstancy. While during certain epizootics, and in certain countries, the results of inoculation on the large scale have been so favourable as to lead even the opponents of inoculation to hope that they were mistaken, in others the mortality has been almost as great among inoculated animals as among those infected naturally. Until we are able, not only to say on what these variations depend, but to control them - until we have found out a method of producing a mitigated form of the disease at will, the problem will remain unsolved.

The practice of inoculation has had its strenuous and ardent advocates in every country of Europe - men who have not only made investigations themselves, but have pressed upon governments the expediency of testing its value by experiments on a large scale. Al1 such proposals have been discouraged by the leading members of the veterinary profession, for reasons which are of a similar nature to those which were urged against the practice of inoculation of smallpox at the end of the last century. In countries or districts in which the epizootic prevalence of Cattle Plague is so general that all animals are certain to be exposed to innumerable sources of infection, it is admitted that the practice of inoculation as a prophylactic is at least defensible, for its effect would be to reduce the duration of the epizootic to that of an individual case, and to settle once for all the loss to the community which would be occasioned by it. It is also very generally admitted that in countries in which the disease is constantly enzootic (supposing such countries to exist, of which there is no evidence,) inoculation is proper, no less on the ground of the probability that every animal will take the disease than for the sake of other countries.* {With reference to the Steppes of Southern Russia special considerations are applicable. In the first place it has been shown on the clearest evidence that in the grey cattle of the Steppes the disease assumes a much milder form than in other breeds, and consequently that inoculated animals recover from its effects in much larger proportion than others; secondly, if it be admitted that the Steppes are the home of Rinderpest and the source from which all epizootics spring, it is clear that if all the Steppe cattle imported into Prussia and Austria were rendered insusceptible of the disease by inoculation, and thereby incapable of communicating it, it would eventually cease to exist in Europe. This is the idea, which has been so perseveringly insisted on by that enthusiastic advocate of inoculation in Russia, Professor Jessen.} But the introduction of inoculation as a general prophylactic measure is condemned by all the authorities. It would be unjustifiable, it is said, not only because the result is extremely uncertain, but also because inoculation cannot be carried out without the constantly recurring risk of originating outbreaks, the extent and destructiveness of which can neither be controlled nor foreseen.

    So long as the main question remains unanswered - so long as we do not know how to produce at will a curable form of disease by inoculation, the conclusiveness of this argument does not admit of dispute. In the present state of our knowledge, it would not even be proper to recommend inoculation of sound animals in plague-stricken herds, as a means of bringing an outbreak of limited extent to a speedy conclusion. We are so unacquainted with the circumstances which determine the severity of its effects, that at present no man would be warranted in advising it, for the probable loss which would be sustained by the inoculation of any given number of animals could only be guessed at, not estimated.

  During the course of the present inquiry 11 animal have been devoted to experiments, having reference exclusively to inoculation. Of these, of which nine were yearlings and two cows, six recovered and five died. In the first inoculations (Nos. 1, 2, 4, and 6), the method which is usually practised in Russia was followed. A curved needle of the same form and size as that used by Russian inoculators, perforated near its point, and armed with a seton soaked with virus, and composed of about half a dozen lengths of white worsted thread twisted together, was passed through a fold of the integument of the neck, previously pinched up between the thumb and finger. The needle having been withdrawn, the thread was allowed to remain in the wound for 48 hours, its ends having been previously tied together. In all these cases the wounds became swollen and inflamed, and in some, subcutaneous abscesses were formed which it was afterwards necessary to open with the knife. The discharge in which the threads were steeped was derived from the eyes and nostrils of a cow in the last stage of Cattle Plague. The period of incubation varied from 48 to 60 hours, and the total duration of the disease from eight to ten days. All of them recovered, the improvement commencing from the sixth day.

  Another series of inoculations (Nos. 13, 17, 18, 19, 20) was performed by injecting the liquid virus under the skin of the perineum by means of a subcutaneous syringe, the quantity employed being in each case half a drachm. By this method no local effects whatever were produced. In No. 13 the liquid employed was serum of blood taken from the heifer No. 11, three days after the first rise of temperature observed in that animal. In this case as the period of incubation extended to six days, being nearly three times as long as in the previous experiments, it was judged expedient to repeat the inoculation with mucous discharge from the eyes of No. 12. Immediately after this had been done, the temperature began to rise, so that it may be presumed that the second insertion was futile. The progress of this case was remarkably rapid, death taking place early on the sixth day, a circumstance which I believe to be attributable to the fact that the animal was previously suffering from pulmonary disease arising from strongyli, as well as from flukes in the liver.

  In the other four cases serum was also employed, but was taken from the cow No. 15, 17 hours after the first rise of the temperature. The purpose of these experiments was to ascertain in the first place, whether in Rinderpest the serum of blood is virulent, and secondly, to compare the effects of matter, taken at the earliest stage of the disease, while the mucous membranes still remain in a natural state, and the animal is to all appearance in perfect health, with those produced by the insertion of morbid secretions collected shortly before death. In all of these animals the incubation period was longer than in the former series, varying from four to seven days. No. 17, which recovered, resembled very closely Nos. 1, 2, 4, and 6, both as regards the progress and character of the symptoms. In Nos. 18, 19, and 20, which died, the disease assumed much the same character as in animals which had been naturally infected, the only remarkable difference being that in No. 20 death occurred about half a day later than usual.

  In two other cases (Nos. 14 and 1.5) the operation was also performed by subcutaneous injection, but here the liquid employed was lachrymal. fluid. In No. 14 it had been kept for seven days in capillary tubes, and had been taken between the fourth and fifth day of the disease, a fact which seems to have some relation to the period of incubation, which in this instance lasted for three days. In No. 15, the lachrymal fluid was collected between the seventh and eighth day from No. 14, the period of incubation was from 48 to 60 hours, and death took place 10 days after inoculation.

  In addition to the animals above referred to, four of the calves sent by the French Government to the Albert College, (to be further mentioned in the section of this Report relating to vaccination,) were inoculated by Mr. Duguid by subcutaneous injection on the l5th of February. Of these, two were inoculated with lachrymal secretion collected from No. 19 on the fifth day of the disease; the other two with the same virus diluted with ten times its volume of milk. The symptoms recorded in these animals show that there was no difference either as regards the period of incubation, the duration of the symptoms, or the mode in which the fatal termination occurred.

  It need scarcely be stated, that the experiments hitherto made have been so few that the conclusions drawn from them as to the effects of the methods of inoculation employed must be rather negative than positive.

  • (1) In the first place, it seems to be tolerably clear that it would be incorrect to say that in any of the cases the disease was modified in the same sense in which small­pox is said to be modified in vaccinated persons, for even in the mildest cases, the development and progress of the disease are essentially the same as those which terminate fatally; 

  •  (2) nor can I for a moment believe that in the mild cases, Nos. 1, 2, 4, and 6, there was any relation between the character of the symptoms and the method of inoculation, not only because in Russia where this method is constantly employed, no such mitigation is observable, but because in a number of animals in which the same method of inoculation has been practiced to my knowledge in England, the resulting disease has assumed a most malignant character; 

  •  (3) it appears to me no less evident that the results were in no way affected by the nature of the virus employed. For, on the one hand, the experiments on serum of blood certainly afforded no ground for believing that a mild form of disease could be produced by that method, while on the other, the results obtained from Mr. Duguid's inoculations with diluted virus, of the calves sent from France, do not encourage any further investigation in that direction.


2. Period of Incubation.

From the experiments already related it is seen that in animals inoculated with virus collected during the third stage of the disease, the first indications of infection exist about two days after inoculation; they also afford some ground for believing that in those cases in which these indications are deferred, the prolongation of the period of incubation was in relation to the period at which the matter inserted was taken.

    In animals naturally infected the period of incubation is probably from four to five days. The following facts may be adduced in illustration: A heifer (No. 10) was bought on the 2nd of January for the purpose of experiments on vaccination. It was ascertained by inquiry from her former possessor, that the stable in which she had been kept for several months contained no other bovine animal, and that she had not been exposed in any way to Cattle Plague. On the 5th of January she was placed in a coach-house which had been for some time unoccupied at Notting Hill, along with two other yearlings (Nos. 11 and 12), three healthy cows occupying a contiguous three-stalled stable. On the 6th she was observed to be unwell, and on the 8th I found that the eruption of Cattle Plague on the lips had progressed to such an extent that it must have existed for two or three days. The two yearlings in the same coach-house were apparently well, but it was thought advisable to remove them to the experimental stable. As will be seen by a reference to the cases, they exhibited the initial signs of Rinderpest on the 11th and 12th respectively, and died on the 16th and 18th. The three cows that remained at Notting Hill, under the charge of Mr. Badcock, were vaccinated by him on the 13th; on the 15th they were reported to be ill, and were subsequently removed to the Albert College. From the appearance of the mucous membrane of the mouth there could, in my opinion, be no doubt that the eruption had appeared on the 14th, and consequently, that the disease must have commenced on the 12th - that is about the same time as in Nos. 11 and 12. Thus after three days exposure to natural infection, from the 5th to the 8th of January, the five animals became affected on the 11th or 12th, and were all dead by the 18th, showing that at least, in one instance, the period of incubation could not have exceeded five days. This result is confirmed by the more exact observations made in the heifer No. 15, in which the first rise of temperature took place just four days after it was placed along with diseased animals in an infected stable.* {Since the above was written the following fact has come under my notice. A bullock was placed, on the 26th of March, in the same stall with another animal, then at the third day of Cattle Plague. The temperature remained natural until the morning of the 31st, but at 3 p.m. on the same day it had risen to 104.0.}





  The steps which were taken at the beginning of the present year, for the purpose of determining the question, whether or not successful vaccination exercises any influence in modifying the progress or mitigating the severity of Cattle Plague, have been already sufficiently detailed in the introduction to this Report.

  The first experiments relating to this special inquiry were made during the last week in January, the results being of such a nature, as to make it appear that Cattle Plague could be communicated with perfect facility to vaccinated animals, either by inoculation or natural infection, and that when so communicated its character was not modified. The question was thus at once conclusively settled; it therefore appeared unnecessary to incur further expense with reference to it, so that, although a large number of animals were purchased for vaccination (amounting in all to 26), only three were exclusively devoted to the object for which they were originally intended, the rest (with the exception of those which unfortunately contracted the disease in the reserve stable at Notting Hill) being employed for other experiments. Of these animals, one (No. 14) was purchased of a gentleman, by whom it had been vaccinated in December 1865, at the suggestion of Dr. Harding of Grafton Street, for the purpose of testing the value of vaccination as a prophylactic against Cattle Plague, while the others ( Nos. 1 5 and 16 ) had been generously presented to the Commissioners for the same purpose, by Mr. Dumbrell of Ditcheling, Sussex. In all three cases, the evidence of good vaccination was conclusive. Of the two fine cows presented by Mr. Dumbrell, one had been vaccinated from the other. The success of both operations was guaranteed by Mr. Holman of Hurstpierpoint, and further indicated in the animal last vaccinated, by the regular form and satisfactory character of the crusts which were still adherent, and in the other by the appearance of the cicatrices. In both, the operation had been performed by four insertions. With respect to the purchased animal, although the visible results were not so satisfactory, it was ascertained on the testimony of Dr. Harding that vaccine matter derived from it had been employed with perfect success, in the vaccination of several children.

    The disease was communicated to two of these animals (Nos. 14 and 15) by inoculation, to the other by natural infection. The calf No. 14. was first inoculated on the night that it was brought to the college, with liquid discharge from the eyes of No. 12. which had been kept for six days in capillary tubes, there being at the time no diseased animal in the stables. As on the third day, the temperature of the body remained unchanged, the inoculation was repeated with virus taken directly from a heifer, at the fourth day of Cattle Plague. The result showed that the second inoculation was superfluous, for on the following morning, the temperature had risen to 105° Fahr., and continued above that height during the further progress of the disease. No other symptoms appeared until two days later, when the animal became constipated and lost appetite, and the mucous membrane of the mouth was for the first time affected in the usual way. Although the disease followed its regular course, it soon became obvious that the case was comparatively mild, for on the sixth day, when the unfavourable symptoms, which are the precursors of death, are as a rule to be looked for, no such change took place. There was no marked prostration, the dejections were still of greater consistence than natural, and liquid food was taken readily. On the seventh clay diarrhaea came on, and the general state of the animal was worse, the evacuations being abundant and foetid, and the discharge from the mouth and nares more profuse; but these symptoms soon receded, and convalescence set in.

  The comparison of this case with those previously observed, in which the disease had been communicated to healthy animals by inoculation, afforded no ground for supposing that the progress of the symptoms had been favourably modified by vaccination; for with the exception of No. 13, all of those animals had recovered, and most of them without any severe symptoms, whereas here the animal was so ill on the seventh day, that it was thought to be dying. In No. 13 the progress of the malady was more rapid, but there the unfavourable result appeared mainly attributable to previously existing disease.

Microscopical Researches on the Disease




Lionel S. Beale (1828-1906) in 1873. With copyright permission from Welcome Institute Library, London.  M16788

Photograph with copyright permission from Wellcome Institute Library, London. 

  [Section omitted] 

Admitting, then, that the active poisonous matter of contagious diseases generally consists of living matter, and that this living matter enters the blood, let us inquire how the living particles may pass into the vascular system where there is no inoculation, no solution of continuity, as far as can be ascertained, in the vascular walls. We may explain the fact, that of a number of persons equally exposed to the influence of a contagious poison, some will contract the disease while others will escape, by supposing that in the latter case the living particles are prevented from passing through the vascular walls, or, coming into contact with the blood, that they do not grow and multiply, but become destroyed, and the substances resulting from their destruction excreted, and at once removed from the body.

  How, then, do the living particles pass through the vascular walls and enter the blood; and what are the circumstances that would favour or interfere with their passage? Thin-walled capillary vessels, as is well known, come very near to the surface in many parts of the body. Those of parts of the mucous membrane of the nose, mouth, and conjunctiva, even in a state of perfect health, are covered with a very thin layer of protective epithelium, while those of the air cells of the lung are practically speaking bare. In many morbid states the epithelial covering of the mucous membranes enumerated above is very soft, and sometimes is reduced to a thin layer of a soft pulpy mucus, in which any foreign particles would very readily become embedded. It is reasonable to suppose that the contagious germs would find in this soft mucus a nidus favourable for their reception, and at the same time soluble materials adapted for their nutrition. They would grow and multiply, and probably minute off-sets from them would soon find their way to the external surface of the capillary walls.

    I have shown that there is strong reason for concluding that when the capillaries are much stretched, as when fully distended with blood, as in the early stages of inflammation, particles of living matter, probably derived from the white blood corpuscles, make their way through the walls with some of the serum, and grow and multiply in their new position external to the vessels.*{On the Germinal Matter of the Blood, with Remarks on the Formation of Fibrin. – Trans. Mic. Soc. Dec. 1863.} An "exudation," therefore, does not consist of mere fluid, but contains particles of living growing matter, which pass with the fluid through the capillary walls from the blood. These particles become the spherical granular cells which are often seen external to the vessels in inflammation. Each absorbs nutriment, and just as in the case of all other kinds of living matter grows, and divides, and subdivides. This view concerning the origin of many of the corpuscles in exudation is supported by the fact that in pneumonia, and in some other conditions in which the capillary distension is very great, blood corpuscles, which are much larger than the particles of living matter just referred to, pass through the capillary walls without the vessels being torn across. And every one who has made very minute injections is familiar with the fact that minute longitudinal rents or fissures may be made quite wide enough for a red blood corpuscle to pass through edgeways without destruction of the vascular tube. It is, therefore, certain that particles of minute size may pass through capillary walls without the occurrence of actual rupture.

    Now the state of things referred to above - a soft, moist state of the mucous surfaces, a dilated condition of the capillaries, combined with a weak, flaccid state of their walls, which would follow long-continued congestion, and which is intimately connected with a weak heart's action and feeble condition of the nervous system, -  are those which would facilitate the passage of such living germs as I am supposing, and is it not probable that these are the very conditions which exist in the organism about to be the victim of a contagious fever? In such cases the composition of the blood is altered, and its fluid constituents manifest a tendency to permeate the vascular walls more readily than in a perfectly healthy state. This state of blood would doubtless affect the nervous centres presiding over the contraction of the arterial walls and regulating the flow of blood through them, thereby influencing the nutrition of the part, and in this way a relaxed state of the arterial walls and a congested state of capillary vessels might be induced, or, already existing, might be increased. It is this low and but too often ill­defined weak state of health that we should endeavour to detect by most careful observation, and at once treat. Nay, it seems to me almost certain that every serious contagious and non-contagious acute disease dangerous to life to which we are subjected is preceded by a condition or system which in many particulars is a departure from health. If this can be altered, the liability to the supervention of the acute attack no longer exists. It is in the direction of anticipating the occurrence of actual, serious, well-marked disease that those most earnest in advancing medicine may reasonably hope to do useful work. And it seems certain, that the more minutely we investigate, the more likely shall we be to learn how to discover and appreciate that slight departure from the healthy state which precedes, and often by some considerable time, the development of many of the most serious and most fatal maladies.


Of the Multiplication and Reproduction of the Contagious Material in the infected organism. – From the observations already advanced concerning the size of the smallest active particles capable of growing and multiplying, it will be inferred that the quantity of material capable of giving rise to a contagious disease is wonderfully small, and that within the organism this minute portion of matter multiplies a million-fold. One or more particles having entered the blood would of course circulate with that fluid. It is possible that the particles would multiply to some extent while actually circulating; but it is probable that many of them would fail to traverse the capillary vessels, being obstructed by the masses of germinal matter which project into their interior and in which, or in the white blood corpuscles, they might even become embedded. The conditions to which they are exposed in the capillary vessels would be more favourable to their rapid multiplication than those present in the circulating blood, and they would therefore grow and increase considerably in this situation.

     We have now to enquire more precisely into the circumstances under which the wonderful increase of the poison is brought about. There are two view essentially different from one another, which may be supported by different arguments.

  • 1. It might be maintained that the contagious material actually passing into certain portions of the living germinal matter of the organism might excite in these new actions, and cause them to divide and sub-divide very actively, and communicate to them the same properties which the original particles possessed, somewhat in the manner in which the wonderful powers existing in connexion with the germinal matter of the spermatozoon are communicated to that of the ovum and affect to some extent every one of the multitudes of masses resulting from its division.

  • 2. The contagious particle or particles having gained access to the fluids of the uninfected organism may absorb nutrient matter, grow and multiply, giving rise to a progeny exactly like themselves in every particular.

   In the first case the actual living matter of a healthy organism is caused to take upon itself a new and peculiar action in consequence of the influence of another kind of germinal matter upon it. In the second the contagious material simply grows and multiplies at the expense of the pabulum.

   It is open to discussion which of these two views is supported by the greatest number and most pregnant facts. I incline strongly to accept the latter as the more probable of the two.

   It may, however, be fairly asked, if, when a pus cor­puscle from the surface of the conjunctiva of a person suffering from purulent ophthalmia, or when a particle of gonorrheal pus comes into contact with an uninfected conjunctiva and grows and multiplies, establishing a similar morbid condition to that in operation upon the surface where it grew, the multitudes of resulting pus corpuscles are the direct descendants of the pus corpuscle or are derived from the germinal matter of the cells of the conjunctiva which are modified in consequence of its action upon them?

    It seems to me probable that the corpuscles capable of exciting a new action upon an unaffected surface are the direct descendants from the original corpuscles which excited that action. Not only so, but I believe they take the nutrient material which was destined for the nutrition of the normal cells, and live at their expense. Just as in the case of cancer, the adventitious rapidly growing germinal matter takes the nutriment destined for the normal tissue, and even feeds upon the latter in consequence of its powers of growth being much more active.

    It is most probable, I think, that in the case of the specific pus corpuscles growing upon a mucous surface the germinal matter of the normal cells may increase and multiply too. Indeed, in some instances I am sure that this is the case. So that there are two distinct processes going on; 1, the multiplication of the specific corpuscles, and 2, the multiplication of the germinal matter of the normal cells modified in consequence of the altered circumstances to which they are exposed. And it therefore follows that not every one of the pus-like bodies formed is capable of exciting the specific action, but the specific bodies outstrip in the rate of their multiplication, to so great an extent, the masses resulting from the normal germinal matter, that the number of descendants of the latter would be comparatively insignificant and would soon be completely overwhelmed by the former.

    Upon the whole, then, I venture to think that the millions of contagious particles produced in the organism in an eminently contagious disease, are all the direct descendants of the very few, or perhaps even single particle first introduced; just as the millions of bacteria and fungi developed in certain decomposing organic matters in the course of a few hours may have been produced from one or at most a very few particles. And that although in the secretions upon the mucous surfaces, and in internal parts, there may be many masses of germinal matter resulting from the increased access of pabulum already many times referred to, these latter do not form the active elements of the contagious material or contagium.


Concerning the possibility of the particles of contagium passing into the substance of normal living germinal matter. - It is true that in the substance of many masses of germinal matter found in the secretions and discharges of animals dying from Cattle Plague, and of many other diseases, some minute particles which would ordinarily be termed granules, which refract the light very highly, and probably have been often mistaken for minute oil globules, may be invariably observed in great number. The nature of these particles is not known. They are however met with in almost all kinds of living matter with which I am acquainted, and different kinds are observed. In Fig. 71 at a. some are seen in a very minute amoeba. In Fig. 15 some are seen in masses of germinal matter from the milk. It seems to me probable that some of these particles have originated in the germinal matter itself, while others have passed into it from without.

     Now it is certain that such particles are very numerous, and are commonly found in masses of germinal matter so situated as to render their entrance from without, not only possible, but probable. The fact of the amoeba opening itself as it were, and then enclosing upon foreign particles, and embedding them in its very substance, is well known. Nor is this a phenomenon peculiar to the amoeba, but it is possessed by other kinds of germinal matter. And now that the supposed importance and even the actual existence in many cases of the cell-wall have been disproved, and the active, spontaneous movements which used to be called amoebiform, because it was supposed they were peculiar to the amoeba, have been proved to be common to living matter in general, it is probable that this and other properties, equally characteristic of all kinds of matter in a living state, will be admitted.

     It must then be regarded as at least possible that particles of contagious living matter less than 1/100000 of an inch in diameter might pass into the substance of a white blood, lymph, or chyle corpuscle, and thus embedded, the particle might be carried to all parts of the system. The matter itself might increase and multiply in the corpuscle, destroying it and living at its expense until the new collection attained a size larger than that of the corpuscle. Or, the foreign living particles in the white blood corpuscle might interfere with its division and sub-division, and the germinal matter of the cor­puscle itself, attain a size larger than ordinary. Or the presence of the bodies supposed might cause the death of some of the particles of germinal matter and the formation of oil globules and other substances which might go on accumulating until the white corpuscle became too large to traverse the smaller capillaries. The phenomena above referred to, would not only seriously interfere with the growth and nutrition of the white blood corpuscles, but would prevent the material under­going conversion into red blood corpuscles. And in consequence of the diminution in number of the red blood corpuscles, and the reduction of the total quantity of blood in the system, various secondary phenomena would follow.

     But in whatever way the minute particles of germinal matter supposed to be included in the white blood corpuscle might cause their enlargement or interfere with their function, impediment to the free circulation of the blood in the capillaries must be induced. The minute particles now stationary would rapidly increase and multiply, and some might make their way through the vascular walls towards the surface or into the surrounding textures.

    The minute particles embedded in the germinal matter sometimes so closely resemble minute vegetable germs that in some cases it is difficult to believe they are not of this nature and have gained access from without. In other cases these particles are of the nature of nucleoli, and have originated in the germinal matter itself, while I am quite certain that some of the minute highly refracting particles embedded in the white blood corpuscles, pus corpuscles, and some other masses of germinal matter, result from changes occurring in the germinal matter itself, and are closely allied to fibrin.* {See my paper “On the Germinal Matter of the Blood; with Remarks on the Formation of Fibrin.” Trans. Mic. Soc. Dec. 1863.} I am, however, not able without further investigation to pursue this part of the inquiry.

     Without, therefore, pretending to be able to identify the actual materies morbi of the Cattle Plague, or to distinguish it positively from the other forms of germinal matter present in the fluids, on the different free surfaces, and in the tissues of vast numbers, I think the facts and arguments advanced in this paper tend to prove;

  • first, that it is germinal matter;

  • secondly, that the particles are not directly descended from any form of germinal matter of the organism of the infected animal, but that they have resulted from the multiplication of particles introduced from without;

  • thirdly, that it is capable of growing and multiplying in the blood;

  • fourthly, that the particles are so minute that they readily pass through the walls of the capillaries, and multiply freely in the interstices between the tissue elements or epithelial cells;

  • and lastly, that these particles are capable of living under many different conditions - that they live and grow at the expense of various tissue elements, and retain their vitality, although the germinal matter of the normal textures after growing and multiplying to a great extent has ceased to exist.


The reader wil1 naturally ask which of all the particles seen in the secretions from the nose and eyes, intestines, vagina, &c., are the particles of contagium, for it has been proved that in all these the contagious property resides. He will probably have gathered from the statements made that I regard some of the most minute particles present to be alone the active agents, while the epithelial particles themselves, the fungi and bacteria, are probably as passive as the oil globules or crystals of triple phosphate commonly met with. Particles which I believe to be contagious are represented in Figs. 21, 25, 26, 33, 35, 36, 67, and the granular matter amongst the bundles of fibrous tissue, represented in Figs. 18 and 19, I think consists entirely of particles, the smallest of which would induce the Cattle Plague, if introduced into the blood of an uninfected animal. Figs. 7, 8, 33, 35, 36, represent particles of the suppose “contagium” or active contagious matter in the vessels. It would, I think, be quite possible to devise experiments which would determine positively which is the real contagious matter.

   The real contagious material has passed unnoticed and has really formed part of what has been called debris and granular matter. By the carmine fluid we can however distinguish particles of germinal matter from fat globules, myelin particles, and other debris. Nor are observations and experiments upon this most interesting question concerning the nature of contagium limited to Cattle Plague. Although this disease affords, in very many ways advantages for study far greater than many other contagious maladies, and deserves on many grounds the most thorough and extended scientific investigation, it is probable that many of the questions of the greatest general interest may be successfully worked out by studying other contagious maladies affecting man or animals.

Of the particles of Contagium. - It has been proved experimentally that from the breath of the diseased animal and from the air in the neighbourhood, matter can be obtained which possesses contagious properties. I have endeavoured to ascertain if such particles as I suppose to constitute the contagium could be actually demonstrated by microscopical investigation with the aid of the highest powers. Mr. Crookes has for some time past been investigating this part of the subject, and has obtained some very interesting and important experimental results. He has had the kindness to give me a tube in which a piece of wool had been placed and exposed to the breath of a deceased animal and fully impregnated with contagious matter, and another tube through which the breath of an animal dying from the disease had been passed. I moistened the wool and the tube with perfectly pure glycerine and sub­jected this to examination with the 1/50th.

     Although in each case I have seen particles resembling those already referred to many times in my report, I cannot attach much importance to these two isolated observations, or look upon them as trustworthy, for in the first place the number of minute particles of various kinds present makes it difficult to identify with any confidence the supposed particles of contagium; secondly, as there are undoubted sporules of' fungi, I could not prove that the very minute particles which I should be inclined to regard as the contagium had not been developed from these; thirdly, it is desirable never to place much reliance upon only one or two observations of this character.

     At the same time it is only right to state that the piece of wool in one of the tubes through which the air had been first filtered exhibited a much greater number of minute particles, resembling those which I regard as particles of contagium, than were obtained from the second piece of wool at the other end of the same tube by which the air was subjected to a second filtration. I do think, however, it might be possible to determine the question from this experimental side. The microscopical part of the investigation presents so many practical difficulties that I should not like to enter upon it without performing in the first instance a great many preliminary experiments, so as to ascer­tain by experience the most convenient and delicate methods of examination.

     In conclusion, I will attempt to account for the phenomena which succeed one another, in what I believe to be the order of their occurrence in a case of Cattle Plague, from the time when the con­tagious poison enters the body to the death of the animal.

     With regard to the nature of the contagium itself evidence has been adduced to show that it consists of very minute particles of matter in a living state, each capable of growing and multiplying rapidly when placed under favourable conditions; that the rate of growth and multiplication of these minute particles far exceeds that at which the normal germinal matter of the blood and tissues multiplies, and that they appropriate the pabulum of the tissues, and even grow at their expense.

     Let us suppose that some of the living particles of contagium derived from the infected animal, so light that they may have been wafted long distances by currents of air, but yet capable of effectually resisting the influence of external conditions to which they may have been exposed in their transit, reach an uninfected animal. Coming into contact with the soft and moist mucous surfaces, and finding a nidus suitable for their lodgment, and pabulum fit for their nutrition, they grow and multiply.

     It is at least doubtful if such living particles could take the further course about to be described, if the organism were in a perfectly healthy state. But in the present state of our physiological knowledge of man and domestic animals it is difficult or impossible to distinguish the state in which there is a susceptibility or predisposition to take a contagious malady, from conditions of system which, not necessarily characterised by robust health, are nevertheless, consistent with work, activity, and longevity. In fact we do not possess, at the present time, sufficiently exact data to enable us to appraise with anything approaching to correctness and certainty the value of individual life.

     In an animal about to be infected with Cattle Plague it appears probable that, the minute living particles having reached the surface of the mucous membrane, perhaps already rendered suitable for their nutrition by previous morbid changes, gradually multiply amongst the soft epithelial particles until some of those produced reach the walls of the capillaries almost immediately beneath. It is possible that some of them may be drawn down the windpipe during inspiration, or even into the air cells of the lung. In the latter case they would gain a very ready access to the surface of the capillary wall.

     We may suppose that at the time the particles come into contact with the vascular wall the capillaries happen to be distended, and consequently their walls so thin as to permit small particles to pass through them. Such a state would obviously favour the entrance of minute particles into the blood. One can conceive them gradually extending like particles of an amoeba, and slowly insinuating themselves through the capillary wall, or they might become embedded in the germinal matter of the capillaries, and in this way gain access to the blood. Having reached the interior of the vascular system, they would circulate with the blood, and for a time would give rise to no symptoms whatever; but in consequence of possessing highly active powers of growth they would grow and multiply, increasing at a greater rate in proportion as their numbers increased [i.e. exponentially]. They would soon derange the normal changes going on in the blood; many would probably soon become adherent to the wall as they traversed the more minute capillary vessels, and growing and multiplying in this situation would seriously impede the circulation of the blood, partly perhaps acting mechanically, partly by deranging the nutritive changes occurring in the vessels and in the tissues external to them. Derangement of nervous action would soon follow, and upon sensitive surfaces impaired or perverted sensation, and in the voluntary muscules feeb1e and irregular contractions would result, while the movements of the involuntary muscular fibre which give rise to rumination would cease to be excited, and various phenomena consequent upon the cessation of this important process would follow. Perhaps rigors, partly the restult of direct, partly of reflex, action, might occur about this time.

    The heart's action increasing in frequency during the early period of the disease would perhaps slightly retard the tendency to the capillary stagnation; but the causes which led to the original congestion continuing, the impediment would gradually increase, and the capillaries would become more dilated. Increased erudition, and here and there haemorrhage, would occur; the germinal matter of the capillary vessels and small veins, and that of the tissues external to these absorbing the transuded fluid would increase considerably in amount, and it is probable that this change is intimately connected with the increased development of heat, which almost constantly occurs at this stage of the disease.

     The circulation now becoming weaker, while the accumulation in the capillary vessels still continued, complete stagnation of the blood in certain of the capillaries would occur, and the number of foci would gradually increase. The blood in the vessels first affected would lose its colouring matter, while its white corpuscle s and the living particles of contagious material would increase and multiply. Perhaps from being surcharged with materials requiring excretion, or perhaps in consequence of these not being in a proper state for elimination, the blood does not flow freely through the vessels of the various excreting organs, liver, lungs, and kidneys, and the action of other secreting glands soon ceases from the same circumstance.

     As the capillary congestion extended from the point at which it commenced as from a centre, and as the centres of congestion themselves in the various tissues increased in number, alterations in the chemica1 composition of the mass of the blood still circulating in the system must result, and this would still further aid to the mischief.

     After the blood has remained stagnant in the vessels for a short time, it undergoes change in colour, and the dark appearance at first seen passes through various shades until a dusky greenish hue familiar to all who have observed post mortem appearances results.

    In a severe case the patches of capillary congestion increase in number from day to day, and are much more numerous in some parts of the body than in others. In this disease the mucous membrane of the alimentary canal seems to be specially affected, and in many cases the changes resulting from stagnation of the blood lead to complete disorganization of the tissue. There is no inflammation, but death of a portion of the tissue may occur from complete cessation of the circulation in the vessels which supply it. In the majority of cases, however, the animal dies before the morbid changes have reached this degree; but it is common enough to find a shrinking and wasting portion of the mucous membrane corresponding to the congested vessels, as, for example, in the fourth stomach. In the small intestine the effects of the stagnation of blood in the capillaries are often complete destruction of a number of the villi, a morbid change which would alone cause the death of the animal.

     The congested state, however, is not confined to the mucous membrane of the gums, mouth, air tubes, and almost the whole tract of the alimentary canal. It affects also the capillaries of the skin, inducing first a red rash, commonly distinct upon the almost naked skin of the udder, but by no means limited to this part of the body, and in many cases leading to morbid changes in the cutis and cuticle constituting the eruption.

    In consequence probably of the alteration effected in the mass of the blood by the occurrence of the local congestions, and partly perhaps from the congestion in the capillaries of the mucous membrane of the bronchial tubes and the lungs themselves, partly in con­sequence of impaired muscular and nervous action, the process of respiration becomes seriously interfered with. A remarkable emphysematous condition of the lung, which in some cases extends to the areolar tissue of the body, results.

     It need scarcely be said that many of these changes act and react upon one another. The heart's action gradually becoming more and more feeble, fails to propel the now seriously altered blood, even through those capillaries which still remain pervious, the temperature falls several degrees, and the action of the great nervous centres becomes more and more feeble and at length ceases.

     Perhaps the extreme degree of congestion resulting from changes induced by the enormous multiplication and accumulation of the minute particles of contagium in many capillaries of the skin and mucous membranes, may be an indication of a tendency to its elimination from these points; and it seems not improbable that if a sufficient proportion of the blood could be kept circu­lating in the majority of the capillary vessels, while at the same time, time was allowed for the elimi­nation of the poison from these surfaces, and especially if the free action of the excreting organs could be encouraged, by which the materials in the blood re­sulting from the action of the Contagium in that fluid would be at once eliminated, the life of the animal might be much prolonged or saved. But when stagnation of the blood has actually occurred in a great number of spots in different parts of the body, more especially if in consequence of this and the contact of irritating materials resulting from decomposition of the food, disorganization of the villi has actually taken place, recovery would seem to he impossible. And even if the recovery of an animal after a severe attack of fever could be brought about by great care, practically this would be useless, because the expense of a long convalescence and the nourishment requisite to restore him to his previous weight would exceed the value of the beast.

    The particles of contagium, which have greatly multiplied in the stagnant fluid within the capillaries, readily make their way through the capillary walls, probably with a small quantity of serum, and become mingled with the cells, &c.; which are being detached from the surface; while in the case of the cuticle, where these cells form a firm investment, the particles of contagium multiply and cause portions to be detached in flakes. From every part of the alimentary canal as well as from the skin and probably from the glands connected with those surfaces, the pouring out of the living particles of contagium proceeds, and continues till death occurs. These retain their vitality for a long time after death, and it appears probable that they are not at once destroyed, even when the decomposition of the surrounding organic matters has commenced.

     In the fourth section of my report, I have made use of many facts obtained in the course of other inquiries, and the observations on the pus corpuscle and the movements of living matter were advanced in the lectures I delivered at the Royal College of Physicians, in 1861 and 1865.

    If any apology were needed for the introduction of speculative notions is this report upon the Cattle Plague, I would venture to remark that I found it impossible to prosecute my inquiries and discuss the various questions which presented themselves for solution without resorting to hypothesis, and I think that one method by which we are likely to succeed in gaining real information upon the essential nature and mode of propagation of contagious diseases, as well as upon other complex physiological and pathological questions, is by testing the validity of various hypotheses which obtrude themselves upon the mind of the observer, one after another, as the inquiry slowly proceeds step by step.

     I have to regret that my report contains some repetition, and that I have been precluded from con­densing it into a much smaller space. These great faults would have been corrected had I been able to devote more time to its preparation.



On the Application of Disinfectants in arresting the spread of the Cattle Plague





William Crookes 1832-1919



    1. Previous to my receiving instructions from the Royal Commission for inquiring into the origin and nature of the Cattle Plague, I had devoted considerable attention to the investigation of the applicability of disinfectants to the prevention or cure of this pestilence, ever since its first appearance in England, and had tried numerous experiments both in the laboratory and also on a large scale in farm­yards. I was therefore not unprepared to commence at once the practical operations which it was considered desirable to carry out.

    2. As to the bare fact of the infectious*  {I have throughout this report used the word “infectious” in preference to “contagious.” The limitation to actual contact involved in the word contagious, and the popular opinions which the use of these words foster, that some diseases are infectious and not contagious, whilst others may be contagious though not infections, imply a far more profound knowledge of the way in which diseases are transmitted than we yet possess. I therefore prefer the wider term infectious, as being more applicable to our present knowledge on the subject.}  nature of the Cattle Plague all are agreed. That contamination of some kind is communicated from a diseased to a healthy animal is obvious to every one; but when we inquire by what agency the disease is carried, the answers are of the most conflicting kind. Something, evidently a material substance, passes from one beast to another; but what is this something? Is it a solid, a liquid, or a gas; living or dead; an animal or a vegetable germ ; a poison, virus, or ferment? Each of these views has found advocates, and in favour of each something may be said.

    3. There are weighty reasons for deciding that the infecting matter is neither a gas, nor even a volatile liquid. The almost infinite attenuation which a gas undergoes owing to its rapid diffusion into the atmosphere, would render its supposed noxious influence imperceptible a few yards from the focus of infection. Moreover, the infection is capable of being carried considerable distances in clothing or running water, and in a variety of ways incompatible with the behaviour of gases. For these reasons, and many others unnecessary to adduce here, it seems clear that the disease must be communicated by the agency of solid, non-volatile particles.

    4. The specific disease-producing particles must moreover be organized, and possess vitality; they must partake of the nature of virus rather than of poison.*  {The words virus and poison are generally regarded as synonymous. It would be more convenient, and would tend to promote accuracy of thought, were the distinction here made, generally adopted.} No poison yet known to chemists can approach, even in a faint degree, the tremendous energy of the active agent of infectious diseases. A poison may be or organic, but it is not organized. It may kill with far greater rapidity than the virus of infection, but, unlike this virus, it cannot multiply itself in the animal economy to such an extent as to endow within a few hours every portion of its juices with the power of producing similar results. A virus, on the contrary, renders the liquids of an infected animal as virulent as the original germ. Strychnine may be regarded as the type of [example of] a poison, and vaccine matter as the type of [example of] a virus.

    5. Many considerations tend to show that the virus of Cattle Plague is a body similar to vaccine lymph, and consists of germinal matter, or living cells, possessing physiological individuality, which if not exposed to extremes of heat, cold, or dryness, are capable of preserving their activity for a certain time outside the living organism, of adhering to material objects, and of being carried from one place to another by currents of air; each, when introduced into the blood, requires a certain time (known as the period of incubation) during which the septic germs develope and multiply, until they have so far poisoned the blood that the ordinary symptoms of disease become manifest.

     The blood poisoning thus set up may legitimately be called “fermentation;” it is a decomposition caused by the act of nutrition of the living cell, where­by it reproduces in incalculable numbers the specific septic germs which have given it birth. These gradually infest the blood and other animal liquids, and as the disease progresses are discharged from the skin, throat, glands, &c.; the breath, perspiration, and excreta of the animals forming vehicles far the distribution of the virus. By “living” cells, is not meant living, in the sense in which an animal, or even a lower form of infusoria [single celled eukaryotic organism] lives; but living as a seed, or a vaccine matter, even when dried, may be living, inasmuch as it still possess reproductive vitality.

     6. It is by no means certain that the multiplication of these individual cells is the immediate cause of blood poisoning. The analogy of the action of virus on the blood, to that of yeast on sugar, renders it more probable that this is not the fact. In the case of the best known ferment – yeast – its cells multiply by feeding upon the sugar in the liquid; alcohol and carbonic acid being their excretions. It is therefore probable that during the multiplication of the virus cells, they, in a similar manner, impoverish and weaken the blood, by feeding on the same element in it, whilst at the same time they excrete a poison to which the symptoms of the disease may be immediately due.

     7. The foregoing view differs from the prevalent notion that the virus of contagion consists of decomposing organic matter, declining from a complex towards a more simple chemical constitution, and during its degradation inducing decomposition in the neighbouring particles of matter. This chemical theory at first sight appears very plausible; but it fails to satisfy one necessary condition of the present case. It is possible to imagine that the force set free in the declension of a complex chemical molecule to a more simple form will be sufficient to raise a neighbouring molecule to a structure almost as complicated as the original; but according to this view the ferment would be constantly diminishing, whereas in reality it constantly increases in bulk. The hypothesis is therefore insufficient to explain the prodigious procreative power of the original particle. This power belongs only to the nature of an organized germ, capable of producing multiples of itself by a process of nutrition and sub­division. Thus the line of demarcation between organic poison and organized virus appeals to be very clearly defined.

     This necessarily brief outline of the theoretical views which have governed me in the present investigation will, it is hoped, be clearer and more intelligible after perusing the experimental proofs which follow. They have been corroborated by numerous small laboratory experiments, as well as by practical operations at different farm houses.

     8. Whether this theory thus briefly sketched be adopted or not, or whether it be regarded as a provisional scientific artifice, it certainly includes and explains a far greater number of the phenomena of pestilence than any other hitherto propounded. More­over, it is the theory sanctioned by the most influential of those medical philosophers who have the best right to be heard on this subject, and notably by the distinguished Registrar-General, Dr. Farr, who by the adoption of the word zymotic, in his classification of diseases, has implied his adhesion to this theory.

    9. Bearing upon the communicability of this disease are other questions, which hitherto have not received a satisfactory settlement. 

  • How does the virus travel? 

  • What amount of resistance to ordinary conditions of moisture and time does its vitality confer upon it? 

  • Will it propagate and multiply, outside the animal body, under favourable conditions of warmth and moisture?

  • And can we firm any chemical disinfectant or antiseptic which will readily destroy it?


   The extreme communicability of the pestilence may arise either from the eminently diffusible character of the virus-cells, or from their persistent vitality, or from both conditions combined. It is proved that the materies morbi will adhere to clothing, and can be carried a considerable distance in it; that the breath, perspiration, and evacuations of the diseased animal are loaded with virus-cells; and that the secretions from the mouth, nose, and eyes are in a similar condition. It follows, therefore, that the sheds, in which diseased animals have stood, become impregnated with the virus, ready to settle on the clothes of every one who enters; that ponds, streams, and even wells may become contaminated through foul soakage; that a road, over which diseased cattle have been driven, may be poisoned along its whole distance by the evacuations and other discharges from the animals; whilst their very breath, carried by the wind, may plant the seeds of infection in all the healthy farms by which the road passes.

      There is no difficulty in admitting that the infection may travel for a certain limited distance through the air, and it is even likely that it may be carried longer distances by fogs, or heavy vapours, or by the gases of putrid decomposition; but it appears in the highest degree improbable that the germs should be able to retain their vitality for any length of time in the atmosphere.

      10. Sufficient data do not at present exist to decide whether the germs call propagate themselves apart from the animal. Viewing them as of the nature of a ferment, it is not impossible that they may live and multiply in other warm liquids besides the blood; but the most reasonable supposition seems to be that the presence of decaying organic hatter, or the gaseous emanations from putrefying dunghills, preserves, or may even revive, the expiring vitality of germs brought by men, dogs, birds, vermin, or perhaps the wind; whilst the same causes which foster the virus-cells, - dirt, overcrowding, constant rebreathing of their own and the adjacent animals' breath, an insufficient supply of fresh air, the presence of ammonia and other gases of putrefaction, together with inappropriate food, - may establish a deteriorated state of body, which causes the animals to fall ready victims at the first approach of the plague.

     The existence of these unfavourable conditions may account for the fact that on some farms the disease assumes a character so virulent that no remedy or preservative is of any avail against it, every head of cattle being swept off one after another, each attack being fatal within three days (15. 79. 80). In the words of a writer in the Edinburgh Review

“a single spark of infected matter accidentally thrown into the animal economy, thus reduced as it were to a touch­wood state, fires the mass, which burns until it is consumed.”





    11. There appears as yet but faint hope of finding a cure for the disease, and even were medical science to supply that great boon, it would be of little use unless supplemented with vigorous disinfecting measures; otherwise it would be like attempting to put out fire, fed on all sides with inflammable materials. Disinfection must, therefore, be the first consideration, and should be carried as far as possible short of endangering the health of the sound animals by the agents employed. Disinfectants and antiseptics have necessarily a powerful action on vital phenomena; and in some cases it may happen that an animal’s vital powers are so diminished by the disease that it will not have strength left to bear the remedial treatment; but even in this case less harm will be done by its use than if the animal had been allowed to die of Cattle Plague.

     12. Disinfection, in the widest sense of the term, includes deodorization, and means the neutralization of destruction of all substances, arising from putrifying organic matter, or emanating from diseased animals, either injurious to health or offensive to the sense of smell.

     The putrefactive products of animal and vegetable matter are found to consist of some or all of the following gases and vapours: -

Sulphuretted hydrogen,

Phosphuretted hydrogen,


Phosphorus- and nitrogen-bases of complex constitution,

Acetic, butyric, valerianic, &c., acids,

Carburetted hydrogen,


Carbonic oxide,

Carbonic acid,


Various organized animal and vegetable products of little or no activity, and

The special virus of infection. (The latter in an infected district.)

     13. In a more restricted sense, the term “disinfectants” is used to express those agents which destroy organic or offensive matter by oxidation or analogous action;  whilst under the term “antiseptics” are classed those agents which prevent chemical change by destroying the tendency to putrefy. The latter are termed, by Dr. Angus Smith, colytics, from [Greek letters],  I arrest.

     14. Oxidizing disinfectants are by far the best known and most popular, inasmuch as they appeal directly to popular prejudice, by destroying the foul odours which are the usual accompaniments of infection, whilst antiseptics have little or no action on these gases. I hope to succeed in showing that this fallacious mode of estimating the relative value of disinfectants and antiseptics, is one which does great injustice to the latter.

     15. Cleanliness, ventilation, and good drainage have been spoken of as comprising all that is required to preserve cattle from the plague. This is not correct. Due attention to these points will certainly tend to preserve the animals in better health, and will render them more fitted to sustain the exhausting action of the disease; but ventilation, cleanliness, and drainage are unavailing against the importation of the germs of disease from adjacent herds. These measures are of value as they remove what might otherwise become nurseries for infection. A germ from without, falling on to a clean dry stall, is likely soon to die; but if it meet with moisture and dirt, its vitality may be fostered, and the chance of its coming in contact with a healthy animal so much the more increased (10.). Cleanliness, drainage, and ventilation, are admirable adjuncts to disinfection, but it is not safe to trust to them alone to ward off the plague. Ventilation, by allowing a greater number of cubic feet of air per minute to pass over the animals, may be in fact the means of conveying the infection to them. A moderately ventilated shed, in which antiseptics are freely employed, has been proved to be a place far safer for cattle, than an open field; although when the animals have caught the disease, the mortality appears to be less when they are turned out into an open field than when they are kept in sheds.

     16. Dr. Angus Smith, by his exhaustive examination of disinfectants, has rendered it unnecessary for me to search amongst the numerous class of possibly useful bodies for those likely to be of practical value. His results I accept in the full conviction that they are correct; and I proceed to investigate the respective merits of the comparatively small number of agents available for disinfection.


[Section omitted]


    97. In concluding the report of my experiments, I cannot avoid expressing regret that they are not more complete. Had more time been at my disposal, I hoped to have been able to settle certain important questions, relating to the laws of infection, which are necessarily only imperfectly treated in this report.

     Experiments of this kind necessarily occupy much time. Weeks have been spent in the fruitless endeavour to find appropriate spots, where satisfactory experiments could be performed; and when all has been arranged, longer time has elapsed before any result could be established, during which period the experiments required unremitting watchfulness, to guard against the manifold sources of error.

    98. Were time and opportunity allowed me for pro­secuting these researches, I would point out the following experiments, as being likely to yield valuable results: -


  1. Continue the examination of the action of carbolic and cresylic acids on insects, animalcules, and microscopic animal and vegetable organisms, and extend it to xylic acid and other powerful antiseptics of this class, such as eugenic acid, methyl-oxy-phenic, and methy oxy-cresylic acids, &c. (36. 39. 40.).

  2. Try various methods of readily disinfecting sheds, cattle trucks, &c. It is probable that the liquid pulverisers, as used for the inhala­tion of medicated liquids, would rapidly diffuse carbolic acid, pure or in solution, wherever its action was needed. The employment of this instrument will also give the means of employing non-volatile disinfectants, such as per-­manganate of potash, per-chloride of iron, and other metallic salts, for purposes of atmospheric disinfection.

  3. Examine the atmosphere from different parts of infected sheds, with standard solutions of permanganate of potash, and estimate quanti­tatively the organic matter therein contained (57. d.).

  4. Draw infected air through gun cotton, and afterwards dissolve the latter in ether, or other appropriate solvent, and examine the residue under the microscope (57. b. 86.).

  5. Collect the exhaled breath from diseased animals, and cause healthy animals to breathe it. (This experiment must be carefully arranged, so as to avoid communicating infection by other means than through the lungs.)

  6. Draw infected air from, sheds, and the breath of diseased animals, through spiral glass tubes, artificially cooled with ice, or by Krohne and Seseman’s ether spray apparatus, as used for local anaesthesia. Examine the condensed liquid chemically and microscopically (57. c).

  7. With the condensed liquid obtained in the last experiment, inoculate healthy animals, both before and after mixing it with various quantities of carbolic acid or other antiseptics.

  8. With the liquid collected from the eyes and nostrils of diseased animals, inoculate healthy animals; both before and after mixing with it various quantities of carbolic acid or other antiseptics (42).

  9. Inoculate healthy animals with infected cotton wool, obtained as in experiment d. Repeat this, after exposing the infected wool to the vapour of various antiseptics (43. 57. b.).

  10. Try if the infection is produced through the stomach by adding to the food infected liquids.

  11. Try if the infectious matter is on the skin, by washing a portion of it, and inoculating a healthy beast with the liquid.

  12. Condense the volatile matter of the feces of diseased animals, and try if the infection is present in it.

  13. Examine the gas which collects under the skin in cases of emphysema, chemically, microscopically, and in relation to its power of com­municating infection.

  14. Continue the experiments on injecting antisep­tics into the blood of diseased animals (77. to 96.). In this manner, try the action of sulphites, bisulphites, hypophosphites, and the substances mentioned in experiment a. The injections can be repeated several times on the same animal, by tying in the vein, a tube furnished with a stopcock.

  15. Repeat, several times, the experiment of placing together in the same shed a healthy and a plague-stricken animal, and endeavour by any method which promises best to save the diseased animal from death, and avert the pestilence from the healthy one. Previous experiments (56. 65.) show that the favourable solution of this problem is far from unlikely.

  16. Try the preventive. and curative effect, once or oftener in 24 hours, of submitting the animal for a certain time in a small chamber filled with strong disinfecting or antiseptic vapour, so that the whole current of the blood and substance of the tissues may be speedily and strongly impregnated with it (46.).

  17. Repeat some or all of the foregoing experi­ments on sheep; and try any fresh experiments which may be suggested in the course of the inquiry.

    Experiments g, h, and i will show beyond a doubt whether the virus of Cattle Plague is destroyed by carbolic acid. Valuable information would be gained by occasionally pushing the experiments n and p to fatal issue. It is probable that the carcass of a diseased beast, killed by either of these experiments will be found to be efficiently disinfected; and should this prove to be the case, the administration of a fatal dose of disinfectant will usefully replace the poleaxe.

     99. In dealing with the Cattle Plague it is possible to try testing experiments of a nature wholly inadmissible where human beings are concerned; and thus it is feasible to suppose that from the lessons derived from this pestilence we might obtain insight, into means of preventing, or even curing, zymotic diseases. Thus the theoretical views, the experiments, and results recorded in the preceding pages, possess an interest beyond the immediate sphere of Cattle Plague. They point forcibly to the possible prevention and cure of all zymotic diseases which attack the human race, and thus possess a far wider and more momentous significance, than if they related only to cattle. Every argument brought forward, every experiment detailed, and every result obtained in the course of this investigation, apply with overwhelming force to such visitations as typhus and typhoid fever, smallpox, diphtheria., and to that terrible scourge which for some time past has been threatening our shores.

    100. The free use of the disinfecting agents here pointed out might not only save the country from theravages of this pestilence, but it would ameliorate the physical condition of the people. Although foul sewage and putrefying animal matter are probably insufficient to generate the first septic germ of zymotic disease, there can be no question that when such diseases do attack a population they spread with the greatest virulence wherever such putrescent materials abound. Highly important results might be expected to follow the general use of antiseptics, whether applied to farm buildings, where large quantities of manure are produced, or to sewage, whatever its destination,­ whether allowed to fester in cesspools, pollute our rivers, or return to the soil. In tracts of land to which sewage, disinfected with carbolic acid, has been applied, the sheep are free from foot rot, the potatoes from disease. Obnoxious insects, such as turnip-fly, gnats, and dunflies, are absent; and grubs, larva, and the lower forms of animal life, and infusoria (the invariable accompaniments of putrefying matter) disappear; whilst vegetation becomes remarkably healthy and luxuriant. It is also highly probable that those imperceptible, but injurious emanations from the soil, known as malaria, would be destroyed, for Dr. Angus Smith* {On the Production and Prevention of Malaria, by Dr. R. Angus Smith, F. R. S. ‑ Memoirs of the Literary and Philosophical Society of Manchester, vol, i., 1861.} has conclusively proved, that the putrefactive decomposition in soils, which produces malaria, does not take place in presence of very minute quantities of carbolic acid; and Dr. M'Culloch has shown that the unhealthiness of many parts of England may be traced to such exhalations. It therefore may he expected that, by extending the sphere of operation of these preventive appliances, we may not only diminish the loss of much valuable property and much sustenance of the people, but even diminish the risk and extend the term of the natural life of man.

April 25th, 1866.  WILLIAM CROOKES.

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Posted circa 2001 and last edited 24 Jun 2014 by Donald Forsdyke