528 MANUAL OF MODERN FARRIERY 



But while we believe that few cases of tuberculosis 

 in the human subject are traceable to the eating of the 

 flesh of tuberculous animals, we entertain a different 

 opinion as to the propagation of tuberculosis by drink- 

 ing the milk of tuberculous cows, because it is partaken 

 of as drawn from the animal, and rarely subjected to 

 heat or cooking of any kind. 



But even here again, the cases of tuberculosis 

 which owe their origin to drinking the milk of tuber- 

 culous cows, are not so numerous as at first sight 

 would appear, because numerous experiments in the 

 feeding of calves on the milk of tuberculous cows, tend 

 to prove that if the mammary gland be free from 

 tubercular deposits (which in the majority of cases it 

 is), the milk does not produce tuberculosis in the 

 calves fed on it. 



Regarding the hereditary transmission of this dis- 

 ease, until lately it was the unanimous opinion that 

 consumption, or tuberculosis, descended from parent to 

 offspring, and was propagated in no other way, but as 

 it is a parasitic disease, or a disease produced by a 

 specific parasite (bacillus tuberculosis), and without 

 the parasite there can be no such disease, then it 

 cannot be a parental inheritance, or disease flowing 

 from the parents of the affected animal, but a disease 

 associated with, and entirely dependent on, the pres- 

 ence and existence of the bacillus tuberculosis in the 

 body of the affected animal. 



We do not, however, incline to the opinion that all 

 individuals and all animals are alike exempt from, or 

 prone to be attacked by, this parasite. On the contrary, 

 we hold the decided opinion that certain families in 

 the higher and lower animals inherit a condition of 

 body which predisposes or lays them open to be 

 attacked by this parasite. 



