COW-POX. 233 



Cow-Pox (Variolce Vaccince}. 



This very simple affection is not often noticed, and so 

 many forms of eruption are observed on the teats, that it is 

 somewhat difficult to detect the true from false varieties of 

 cow-pox, at certain stages of the eruption. This disease has 

 claimed a very large share of attention on the part of scien- 

 tific men, from Jenner's discovery in the dairies in Glouces- 

 tershire, where he observed that the people milking cows 

 with the cow-pox suffered from an eruption on their hands, 

 but never had the malignant small-pox of the human being. 

 This was the origin of vaccination. 



The cow-pox, like other forms of variola, is a contagious 

 pustular eruption of the skin, running a very regular course, 

 accompanied by slight fever. It is communicable between 

 animals of different species. 



Causes. The primary cause of cow-pox is unknown. The 

 majority of cases occur in spring and summer, shortly after 

 cows have calved. The state of congestion of the udder at 

 this period favours the development of the disease, and it has 

 never been observed to arise spontaneously in bulls, oxen, 

 or heifers, before calving. It is chiefly seen in cows from 

 four to six years of age. Mr Ceely makes the follow- 

 ing sensible remarks on the causes and origin of the 

 disease. Eeferring particularly to the Vale of Aylesbury, 

 he says: 



" The variolce vaccince seem to have been long known in 

 the vale and neighbourhood. They have been noticed at irre- 

 gular intervals, most commonly appearing about the begin- 

 ning or end of spring, rarely during the height of summer ; 

 but I have seen them at all periods from August to May, and 

 the beginning of June. By some it is presumed that cold 

 and moisture favour their development; by others, that the 



