AN OUTBREAK OF COW-POX. 275 



in 1885, a few miles from these farm.s, but on a separate estate, the 

 disease appeared in June and July. 



Origin of the Outbreak. — The author made careful inquiries as to the 

 origin of the outbreak, but beyond ascertaining with certainty that the 

 disease appeared first at one farm, and was conveyed from this to the 

 other farms, all evidence was negative. The milkers were unable to 

 say whether it commenced in one particular cow or whether it broke 

 out in several simultaneously. 



The only information which could be obtained, which was very 

 suggestive, was that the milkers were in the habit of receiving their 

 friends from neighbouring farms on Sundays. The friends would assist 

 in the milking, to get the work done as quickly as possible on these 

 occasions. As it was reported that the same disease had occurred 

 that summer on a neighbouring farm, it is quite possible that it was 

 introduced by one of the milkers' friends. 



Mode of Dissemination. — When the disease made its first appearance, 

 the bailiff, attributing it to the farm being, for some reason, unhealthy, 

 decided to remove the cows to other farms. The herd was therefore 

 divided and sent to two other farms. From these cows the disease was 

 communicated to healthy cows, and, as this interchange was repeated, 

 not only of the cows, but of the milkers, the disease was communicated 

 to four separate farms. 



In all cases the disease was limited to the teats, and was conveyed 

 from the teats of a diseased cow to the teats of a healthy cow by the 

 hand of the milker. In no case was there any evidence of the disease 

 being produced in healthy cows by other means than contact. 



Bulls and dry cows remained free from the disease, while the cows 

 in mUk, numbering about a hundred and twenty, were all attacked, with 

 the exception of about a dozen, which proved to be entirely refractory. 



These facts explain how it is that the disease has been known from 

 time immemorial as the " cow-pox.'' We never hear of cattle-pox or 

 bull-pox. We have not, in other words, to deal with an infectious 

 disease like cattle-plague or pleuro-pneumonia, but with a disease which 

 is communicated solely by contact. 



The disease was only observed in the cows in milk, and was limited 

 to the parts which come in contact with the hand of the milker. The 

 virus was mechanically transferred from diseased to healthy cows, being 

 communicated to all, or nearly all, the animals in the same shed, 

 whether the milker had vesicles on his hand or not. 



Character of the Eruption on the Cow. — In a recent case which was 

 carefully examined the teats were visibly infiamed, partly red and partly 

 livid in colour. On each teat there were vesicles, some broken, and 

 others which appeared to be just forming. In other cases there was 

 nothing more than the remains of broken and dried vesicles, and more 

 or less characteristic crusts on the teats. 



On visiting a byre at the time that the cows were brought in to 

 be milked, it was a striking sight to look along the line and see one 

 animal after another affected with the eruption ; and thus one character 



