272 TUBERCULOSIS 



medium from 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 Perlsucht, in France 

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

 the peritoneum and pleune. In other cases, again, the abdominal organs 

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

 portion of cases 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. 



