TUBEECULOSIS IN ANIMALS 267 



the organs of animals artificially rendered tubercular. The fact that 

 growth did not appear till the tenth day at the earliest, might easily have 

 led to the hasty conclusion that no growth took place. All difficulties 

 were, however, successfully overcome. He cultivated the organism by 

 the above method from a great variety of sources, and by a large series 

 of inoculation experiments on various animals, performed by different 

 methods, he conclusively proved that bacilli from these different sources 

 produced the same tubercular lesions and were really of the same species. 

 His work was the means of showing conclusively that such conditions as 

 lupus, " white swelling " of joints, scrofulous disease of glands, etc., are 

 really tubercular in nature. 



Tuberculosis in Animals. — Tuberculosis is not only the most 

 widely spread of all diseases affecting the human subject, and 

 produces a mortality greater than any other, but there is probably 

 no other disease which affects the domestic animals so widely. 

 We need not here describe in detail the various tubercular lesions 

 in the human subject, but some facts regarding the disease in 

 the lower animals may be given, as this subject is of great 

 importance in relation to the infection of the human subject. 



Amongst the domestic animals the disease is commonest in cattle 

 (bovine tuberculosis), in which animals the lesions are very various, both 

 in character and distribution. In most cases the lungs are affected, and 

 contain numerous rounded nodules, many being of considerable size ; 

 these may be softened in the centre, but are usually of pretty firm 

 consistence and may be calcified. - There may be in addition caseous 

 pneumonia, and also small tubercular granulations. Along with these 

 changes in the lungs, the pleurae are also often affected, and show 

 numerous nodules, some of which may be of large size, firm and pedun- 

 culated, the condition being known in Germany as Perlsueht, in France 

 as pommeliire. Lesions similar to the last may be chiefly confined to 

 the peritoneum and pleurae. In other oases, again, the abdominal organs 

 are principally involved. The udder becomes affected in a certain pro- 

 portion of eases of tuberculosis in cows — in 3 per cent, according to Bang 

 —but primary affection of this gland is very rare. Tuberculosis is also 

 a comparatively common disease in pigs, in which animals it in many 

 cases affects the abdominal organs, in other cases produces a sort of 

 caseous pneumonia, and sometimes is met with as a chronic disease of 

 the lymphatic glands, the so-called " scrofula " of pigs. Tubercular 

 lesions in the muscles are less rare in pigs than in most other animals. 

 In the horse the abdominal organs are usually the primary seat of the 

 disease, the spleen being often enormously enlarged and crowded with 

 nodules of various shapes and sizes ; sometimes, however, the primary 

 lesions are pulmonary. In sheep and goats tuberculosis is of rare 

 occurrence, especially in the former animals. It may occur spontaneously 

 in dogs, cats, and in the large carnivora. It is also sometimes met with 

 in monkeys in confinement, and leads to a very rapid and widespread 

 affection in these animals, the nodules having a special tendency to soften 

 and break down into a pus-like fluid. 



Tuberculosis in fowls (avian tuberculosis) is a common and very 

 infectious disease, nearly all the birds in a poultry-yard being sometimes 

 affected. 



