3/2 AGRICULTURAL BACTERIOLOGY. 



culous animals by tuberculin. Then all of the reacting ani- 

 mals which clinical examination shows to be advanced cases, 

 and all animals that show any signs of disease in the udders, 

 are to be removed immediately and slaughtered, since they are 

 beyond question sources of danger to the herd. The animals 

 that react, but show no other signs of the disease, are to be 

 separated from the rest and placed in a barn by themselves, 

 thus removed from every possible contact with the rest of the 

 animals in the herd. This is not because they are necessarily 

 sources of danger, but simply because there is no means of 

 determining when any one of them may become a source of 

 danger to the animals with which it associates. The healthy 

 (non -reacting) animals are then to be placed by themselves, 

 either in a new barn or in the old barn only, however, after 

 thorough disinfection. By this means a practical isolation of 

 the tuberculous animals is effected. 



If, now, the farmer wishes to preserve the healthy herd from 

 future attack he must take precautions that the isolation is 

 thorough. The isolation may be effected by simply building 

 a partition in his cattle shed ; but if this is done there should 

 be no door in the partition, for such a door will surely result 

 in a carrying of bacilli from one compartment to another. 

 The farmer must remember the facts already pointed out as to 

 the methods of distribution of bacilli. If possible he should 

 have separate attendants for the two herds, and at all events 

 the boots worn in attendance on the infected herd should not 

 be worn in the shed occupied by the healthy animals. He 

 must remove all calves from the infected herd a few days after 

 birth, and bring them up upon the milk of the healthy herd 

 alone. Hereditary tuberculosis is not common, and most of 

 the animals born of the infected herd will, at birth, be free 

 from the disease, and may be kept so by proper care. In- 

 asmuch as the milk of infected cattle is probably the most 

 prolific source of the distribution of the disease among calves, 



