THE COW ELEMENT IN MILK EPIDEMICS 281 



of hair in patches, and a general condition of ill-health. After 

 careful consideration, Mr Power arrived at the conclusion that this 

 cow had been the exciting cause of the outbreak, and thereby 

 opened up a question upon which there has been considerable 

 controversy.^ Into this we cannot enter fully, but for various 

 reasons it is important that the matter should not be wholly 

 avoided. We shall therefore attempt a brief and impartial account 

 of the subject. It will be understood that our aim is a statement 

 of fact or theory and not an argument. Our object is historical 

 and not advocacy. At the outset then, we may say that Mr 

 Power's investigation in 1882 led him to write as follows. His 

 remarks on the matter are of sufficient importance to quote in 

 some detail : — 



" I satisfied myself," he writes, " that it was practically out of the question 



that the milk at the farm had become infected in any of the commonly-believed 



ways that require a human subject as the source of infection : and I think it 



altogether unlikely that commonplace fouling of dairy utensils by polluted water 



or the like, can have here occurred. In the end, I found myself as on a former 



occasion, called upon to face the question whether or not actual cow conditions 



might have been competent for the results obser\-ed, and in considering the 



question I came to see that a hypothesis of cow causation would fit the facts 



[that needed explanation as well as, or even better than, any other hypothesis. 



'If only it could be believed that a single cow of this herd of 60 to 70 cows 



[had been for a limited time capable of affording sp)ecifically infected milk, there 



[was nothing in the routine of the farm dair)' arrangements inconsistent with the 



[milk of such single cow having been distributed among the chums consigned 



rom the farm to London ; and this in such a manner as to infect simultaneously 



Ithe milk service of each London dairy supplied from the farm, and during a 



^certain limited period a considerable proportion of that service. . . . On 



[reference to his (the farmer's) books we found that one of his cows due to 



[calve on the 27th December had calved subsequently to, but within ten days of. 



[that date, and had come into milking for business purposes three or four days 



rafter calving. . . . Upon examination of this cow on the nth February I noted 



[that she had here and there lost portions of her coat, and that her buttocks and 



[posterior udder were fouled and stained by excremental matter, and perhaps by 



^ It must not be supposed that this was the first occasion on which it had 

 [been suggested that disease could be conveyed to man through milk from 

 [diseased animals. In 1862, Gamgee, in reporting to the Privy Council on the 

 [relation of cattle disease to the meat and milk supply, concluded that "the 

 [cause at present operating most actively to deteriorate the milk of cows in this 

 [country is the prevalence of Epizootic aphtha. This disease attacks the human 

 [subject and many cases of communication from cattle to man have been 

 lobserved either from the virus penetrating a wound or passing into the system 

 jwith the milk." This opinion received the support of Sir John Simon. Nor 

 [was this the first occasion on which milk had been shown to be the infective 

 ledium. 



