68 THE DISEASES OF DOMESTIC ANIMALS. 



Infectious Disease." The following is a free translation of the es- 

 sential points of this paper : 



Although heredity is unquestionably a very important cause in 

 the generation of this disease among cattle, still it does not suffice 

 to explain the great extension which the same acquires among 

 them ; especially is it insufficient in answering for the eruption of 

 the disease among cattle in stables where no breeding takes place, 

 or where the young animals are brought in from other places. In 

 such stables other causes must be brought into action, and these are 

 the transmission of the disease from one animal to another. I have 

 observed that when there is in a stable one individual which contains 

 in its organism the conditions necessary to the extension of the dis- 

 ease — tubercular process in the lungs — the disease extends to the 

 other animals — cattle — in the same stable which have been there 

 for a sufficient period. This seems to conform to the fact that 

 tuberculosis is a disease peculiar to our domesticated cattle, but not 

 to the wild ones of the plains, and agrees with the experience that 

 certain stables are looked upon as peculiarly favorable to the gener- 

 ation of the disease. 



Of the peculiar metamorphoses which tubercles undergo, those 

 of caseous degeneration offer the most favorable conditions for in- 

 fecting the expired air of a diseased animal. 



The following cases will answer to illustrate the point in ques- 

 tion : 



Case I. — At the time (1848) that the views of veterinary au- 

 thors were most crude with regard to the nature of bovine tuber- 

 culosis, I had occasion to treat the disease upon a farm where it had 

 prevailed for a long time, and caused much loss to the owner. 



Upon the farm were always kept fourteen milch-cows and cattle, 

 a bull, and four calves. Of these, four head were sold each year, 

 and replaced by the same number of calves. The animals sold 

 were not always of the same age each year ; in one year the two 

 and three year olds would be sold, in another older cows, and the 

 third some of each, according to the fullness of the owner's purse, 

 so that there were cattle on the farm two, six, and twelve years 

 old. Of these older animals, I found on my first examination two 

 afflicted with a rough, dry cough, and with accelerated respiration. 

 As I was aware of the constancy with which the disease had pre- 

 vailed among the owner's cattle, it was my advice to get rid of these 

 two as early as possible. This advice was followed. The cattle 

 were fattened, and upon being slaughtered my diagnosis was con- 

 firmed. 



