EDITORIAL ARTICLE.

EDITORIAL ARTICLE.

--0--

THE CAUSE AND PREVENTION OF WHITE SCOUR IN CALVES.

THE interest awakened in the subject of white scour by the researches of the late Professor N ocard in Ireland during the spring of last year, has been revived by the able paper which Prof. Mettam contributed to the proceedings of the National Veterinary Association at Windermere, and which appears at an earlier part of this number. It is true that Prof. Mettam's paper is not restricted to white scour, but, in point of clinical interest and economic importance, the other morbid conditions of young or newly born animals dealt with in it are quite over-shadowed by that very common disease of young calves which has diarrhcea for its most constant and prominent symptom; and at the Windermere meeting the discussion to which the paper was subjected was mainly directed to the cause and pre­vention of white scour.

I t will be observed that Prof. Mettam considers the cause of white scour to have been finally and conclusively elucidated by the researches which were almost simultaneously carried out by Nocard in Ireland and Lesage and Delmer in France, and he accepts the view put forward by these authors that the cause of the disease is a small ovoid bacterium of the fowl cholera type. Furthermore, he endorses the opinion that the channel by which this organism generally enters the body of the calf is the umbilical wound. The question as to what particular bacterium is the actual cause of white scour is perhaps not one of great practical importance, and, admittedly, it is, from the point of view of prophylaxis, less important than a knowledge of the way in which the agent of infection generally finds admission to the animal system. At the same time, it is undesirable that any views put forward regarding the nature of the causal organism should be accepted as final unless the evidence on which they are based is unassailable, or at least exceedingly strong. We therefore need offer no apology for calling attention to some weak points in the evidence which is held to prove that a bacterium of the fowl cholera type, or, adopting the name suggested by Lignieres, a " pasteurella," is the cause of white scour.

In the first place, it is surely a remarkable fact that, although white scour is held to be a septiccemia, the particular organism which is alleged to be the cause of it appears to be rarely or never found in' large numbers in the blood of affected animals; and that, even in fatal cases, its recovery in pure artificial culture from the blood or internal

EDITORIAL ARTICLE.

organs is a matter of considerable difficulty. [f it were admitted that the disease is not a septic~mia, but an enteritis analogous to human cholera, this difficulty would not occasion any surprise, or constitute a weak link in the chain of evidence; but it is a circumstance deserving of close scrutiny when it is held that the organism in question is not essentially or mainly a bowel parasite, but one which propagates largely in the blood-stream, and is also responsible for articular and other lesions of a localised character. The extent of the difficulty may be pressed home by saying that there is certainly no other disease of a septic;:emic character in which the causal organism is so constantly associated with extraneous or secondary bacteria as to make it a hard task to recover the former in a state of purity from the blood or diseased tissues. We do not forget that an attempt has been made to explain away the objection here raised by supposing that the organism of white scour generates products which have a paralysing effect on the natural defences of the body against bacterial invasions, and that, therefore, the system of a calf which is the subject of white scour soon becomes penetrated by a variety of secondary organisms which may soon come even to outnumber the original invaders. But this sugges­tion is just as unproved as the alleged fact which it is put forward to explain. That such secondary invasions are not uncommon in th~

feeble and dying is well known and generally admitted, but it may unhesitatingly be affirmed that in no known disease are such invasions so constant and extensive as to seriously interfere with the detection of the primary offender. Besides, it is worthy of notice in this connec­tion that when animals were experimentally infected with the bac­terium alleged to be the cause of white scour little or no difficulty was experienced in recovering the organism in pure culture after death. It is a little difficult to understand why in natural cases of the disease invasion by the bacterium of white scour should nearly always be followed by secondary invasions so extensive as to mask the first, whereas in animals experimentally infected with the alleged white scour organism secondary invasions are absent or inconsiderable.

To sum up the objections which may be raised with regard to this point, it may be said that we still lack evidence that this pasteurella is so constantly associated with cascs of white scour as to compel us to believe that it must be the cause of the disease.

\Ve have next to examine another link in the chain of evidence put forward by the discoverers of this particular organism. It is alleged that white scour can be experimentally set up by inoculating calves with the organism in question. The records of the experiments of this kind prove beyond any doubt that the bacterium employed was highly pathogenic to the calves inoculated, the animals succumbing to a- septic;:emic infection, with, in many cases, diarrhcea as a symptom. But it may reasonably be objected that this does not by any means prove that the bacterium producing these deadly effects is the verit-

266 EDITORIAL ARTICLE.

able cause of white scour. There is a possibility of error in con­cluding that, when a calf infected by intravenous injection developes diarrhcea, the disease experimentally set up is white scour.

The same objection applies to the cases in which the animals were infected by the application of pure cultures to the umbilicus. It would be unfair to say that such experiments have no value. On the contrary, they would have had a high value if the evidence as to the constant presence of this organism in predominant numbers in calves suffering from white scour had been satisfactory. But, as long as that evidence is open to impeachment, the fact that inoculations with pure cultures prove pathogenic and induce diarrhcea cannot be accepted as conclusive proof that such cultures contain the organism of white scour.

The question as to what is the common method of infection in white scour is one of great practical importance. Professor Mettam subscribes to the view that the usual, if not exclusive, point of infection is the uncicatrised umbilicus, and naturally one expects to have set forth the grounds on which this opinion is bascd. In this respect Professor Mettam's paper is disappointing. It is possible that the author relied mainly on the prophylactic success which is said to have been obtained by treatment of the navel to prove that the other possible channels of infection may be neglecter!. That line of argu­mentis undoubtedly a very cogent one, and we shall return to it immed­iately. It must be remembered, however, that the umbilicus was pro­claimed to be the point of infection before the prophylactic effect of asepsis of the navel had been proved in practice. The belief that the umbilicus was the common port of entrance of the organism was founded on the fact that calves could be infected and killed, with symp­toms and lesions more or less closely resembling those of white scour, by injecting pure cultures of the organism alleged to be the cause of white scour into the veins, or applying them to the navel, while attempts to infect by administering similar cultures by the mouth failed. Ob­viously, however, this line of argument faJls to the ground if, as we have already shown, there is a flaw in the evidence relied upon to prove that the cultures employed were those of the bacterium of white scour.

If one desires to ascertain whether calves can be infected with white scour by way of the alimentary canal, the proper method of procedure is not to employ cultures of an organism which possibly may have nothing to do with the genesis of the disease, but, at least in the first instance, to try whether the diarrhceic discharges or the diseased tissues of calves affected with white scour are capable of communicating the disease when they 'are administered by the mouth.

It will be noted with some surprise that, although Professor Mettam regards the umbilicus as the common point of infection,

EDITORIAL ARTICLE.

he quotes without dissent experiments by Jensen, who" obtained infection in seven calves by feeding them on milk mixed with intestinal discharge of animals suffering from the disease." Noone is entitled to deny that infection by the mouth is possible, and even the ordinary way in which the disease is contracted, unless he has himself experimented as Jensen did with negative results, or is prepared to show that there was some fallacy in Jensen's ex­periments.

As long as Jensen's experiments and conclusions are uncontroverted, it must be considered highly probable that most cases of white scour are due to infection by way of the alimentary canal.

Lastly, the practical value of navel treatment in preventing white scour, and the support which this lends to the view that infection usually takes place by way of the umbilicus, must be examined. Professor Mettam says, "in my opinion prevention is to be attained by careful attention to the umbilicus." But, somewhat inconsistently, he adds, "but no matter how careful we may be in the umbilical treatment, this must be supported by cleanliness in and about the houses inhabited by the young and their dams. Treatment of the umbilicus may save animals; there is no doubt that thorough hygienic surroundings will cut down the mortality; both should theoretically remove altogether the cause of death. This has been our experience in Ireland."

It appears to be permissible to suggest that, if this second quota­tion is to stand, the first should read, " prevention is not to be obtained by careful attention to the umbilicus." It may also be suggested that, if the umbilicus is the exclusive port of entrance of the germs of the disease, careful navel treatment by itself should, theoretically, altogether remove the cause of death. On the other hand, if in a large proportion of cases infection takes place by the mouth, it would be very rash to say that navel treatment, even when it is carried out in "thorough hygienic surroundings," will altogether remove the cause of death-that is, assuming that the intestinal discharges of diseased calves contain the agent of infection. However, it will be observed that, whatever one might have been entitled to expect theoretically, Professor Mettam's experience has been that the cause of the disease has been altogether removed in Ireland by combining navel treatment with strict attention to the hygiene of the byres and calf-houses. One could heartily wish that this experience had been universal, but, unfortunately, it does not appear to have been general even in Ireland.

In the course of the present year! a report has appeared setting forth the results obtained on a number of selected farms on which the calves were treated in accordance with the recommendations

1 "Journal of the Department of Agriculture and Technical Instruction for Ireland," March 1903.

268 EDITORIAL ARTICLE.

made by the late Professor Nocard, the navel treatment being aiso supplemented by thorough disinfection of the byres and calf-houses. On a number of the farms the treatment was carried out under the supervision of a person" sufficiently skilled to direct operations, and to ensure to the treatment a fair trial." At the remaining farms the carrying out of the treatment was entrusted to the owners.

The following table is taken from the report :-

No. of Cal1:CS No. treated No. treated 1 J.Ymne of Centre. trented No. died. 1mdeJ' No. died. ~(,:rt{le?' poytial No. died.

by O'lOners. Supe1"I:Mioa. Supervision. i ---------- ---- --- \--Bansha 6 4 22 7 19 i 8 Feenagh 6 4 16 6 6 --

Murroe 7 I 17 2 - ! -

Newcastle West I I 20 8 2 2

Liscarrol 18 8 22 IS - .-

Bunratty : \--;8 - 49 2 2 J

---I ---

TOTAL 18 '46 40 29 I I

The comment which the writer of the report makes upon the results indicated by the figures in the above table is that they are "far from satisfactory." Moreover, the leaflet which the Irish Department of Agriculture is now issuing for the guidance of farmers contains the statement that, "Navel treatment without repeated and absolute disinfection will NOT be successful," and concludes with the warning, "The main point in prevention is disinfection of the premises. Half measures will not be effective."

In face of these admissions, it is not possible to agree with Professor Mettam's optimistic estimate of the beneficial effects of navel treatment, even when it is supplemented by thorough cleansing and disinfection of the premises. It is also impossible to extract from the results obtained in Ireland any support for the view that the disease is always or generally umbilical in its starting-point. On the contrary, they strengthen the opinion that umbilical infection is not responsible for more than a minority of the cases of so-called white scour, and that diarrhceic discharges are the vehicle, and the mouth the usual port of entrance, of the agent which is the cause of the disease.

We do not pretend to know what the author of the Irish leaflet from which we have quoted means by absolute disinfection, nor can we conct!ive how anything deserving of the name can be obtained in an inhabited calf-house. We agree, however, that isolation of the already affected calves, combined with repeated and thorough cleans­ing and disinfection, must be made the keystone of preventive measures. Unfortunately, it cannot be said that, even theoretically, these measures ought always to succeed in arresting the spread of

CLINICAL ARTICLES.

the disease. In this connection it must be remembered that a diseased calf is one which harbours the germ of white scour, and that, just as with many other bacterial diseases, this abnormality may not be manifested by any pronounced symptom of disturbed health. Hence, in any outbreak of white scour it may be practically impossible to distinguish with certainty between the infected and the non-infected animals, although that is precisely what is of cardinal importance when one wishes to arrest the spread of the disease. In short, the difficulty in preventing white scour is just the same as that with which we have long been familiar in the case of other' contagious diseases, such as glanders, tuberculosis, and pleura-pneumonia.

C LIN IC A LA R TIC L E S.

--0--

A CASE OF CYSTIC CANCER OF THE LIVER IN A SHEEP.

By J. F. HODGSON, M.D., Ch.B.Vict., Deputy Medical Officer of Health, Halifax.

Cystic cancer of the liver is an exceedingly rare form of disease in man,I while cancers of any variety are uncommon in cattle and sheep.2

In the public slaughter-house at Halifax over 17,000 sheep are killed annually, yet during the last four years, for certain, only in one case has cancer of the liver been found. It must be borne in mind, however, that the chances are against a sheep with such a rapidly fatal disease ever reaching the slaughter-house, but still, I think, the figures show the great rarity of the disease.

In the case under notice the liver weighed 17 lbs., and was enormously enlarged. Only a very small portion of liver tissue was left, and this had on the surface the appearance of a coarse cirrhosis. The rest of the surface presented a very irregular bossy appearance. On section the small portion of liver tissue was seen to be cirrhotic and slightly fatty, while the rest of the organ was made up of nodular growths and cysts. In fact, the general appear­ance of the liver would almost lead one to think . that it was composed of little else but cysts in a fibrous network. The newer growths were of a greyish yellow colour, of fairly firm consistence, and generally globular in shape. When these nodules got beyond the size of a cherry softening occurred, leading to the formation of cysts, which contained blood and debris. The cancerous walls of the cysts were well marked, and the spaces between

1 Coats "Manual of Pathology. " pp. 906, 907. Hale 'White "Tumours of ihe Liver in Allhutt's System of Medicine," vol. iv., p. 211.

2 \Valley's "Meat In~pection," p. 53.