116 ANNUAL REPORT OP THE Off. Doc. 



disturbed twice a da}' h}' the milker, secondar}' conditions may arise 

 that cause serious results. 



Cow pox is a fever characterized by the occurrence of vesicles 

 upon the skin of the teats and udder, thi«j;hs, abdomen or other parts 

 of the body. The vesicles occur four or five dajs after exposure by 

 contact. Tli(> vesicles are transferred in a day or two into postules; 

 gradually the layer of cells covering them is softened, then it breaks 

 away, leaving a raw surface which covers with a scab and heals 

 more or less slowly. The whole course of the disease, from the 

 .appearance of the vesicles to complete healing may not be more 

 than ten days. 



The disease is verj' mild and without special significance ex- 

 cept in milking cows. As a result of the manipulation incident 

 to milking, the vesicles are broken, the raw surface beneath be- 

 comes inflamed and suppurating sores develop. The surrounding 

 tissues become inflamed so that the teats and skin of the udder 

 are swollen, reddish, sensitive and of higher than normal tem- 

 perature. The inflammation thus engendered may extend into the 

 cavity of the teat or milk cistern and sometimes leads to an in- 

 fection of the substance of the udder. This infection is not a cow 

 pox infection, but is an infection with streptococci, the germs caus- 

 ing suppuration and present on account of the preparation that 

 has been made for them by the cox pox infection. The infection 

 of cow pox and the purulent infection may be carried upon the hands 

 of the milker from cow to cow until a large proportion of the mem- 

 bers of the herd are affected. 



The passage of this disease through a. herd is slow, and it may 

 require from two to four months for it to disappear, and after it has 

 disappeared it is likely to have left behind a number of permanently 

 damaged teats and udders. The damage consists in deformities 

 of teats due to the contraction of scar tissue, that occurs where 

 there was much loss of tissue from deep or extensive ulceration; 

 from stricture of the teats; from rough, dry irritable skin cover- 

 ing the teats, that is constantly subject to irritation and cracking; 

 from the growth of callosities; from long continued streptococcus 

 infection of the udder and from the permanent destruction of quar- 

 ters of the udder as a result of severe mastitis following such in- 

 fectious. 



After cow pox seems to have disappeared from a herd of dairy 

 cows as an acute disease, it is found that the infection lingers 

 in the premises or upon the animals for a period of several months. 

 Consequently, other animals that are introduced into the herd are 

 exposed and are likely to become infected if they have not previ- 

 ously suffered with cow pox. 



Since cow pox in itself is a mild disease, and since bad conditions 

 that follow in its wake are the result of secondary infections and 



