430 DISEASES OF CATTLE. 



(1) Disease of the bones is not unknown, although very rare. 

 According to Walley, it appears chiefly in the spongy bones of the 

 head and backbone and in the long bones of the limbs. Occasionally 

 the ends of the bones, where they are covered by the synovial mem- 

 brane of the joints, are dotted with tubercles. The muscular system 

 itself is very rarely the seat of tuberculous deposits, although the 

 lymphatic glands lying near and among the muscles may be not 

 infrequently diseased. 



(2) Whether tubercle bacilli are found in muscle j nice independent 

 of any tuberculous deposits is a question which must be approached 

 experimentally. There is on record a great variety of opinions on 

 this matter, some authorities considering all flesh from tuberculous 

 animals unfit for food, while others hold a contrary view. Experi- 

 ments have shown that in rare cases the flesh of tuberculous cattle 

 contains a small number of tubercle bacilli. In Germany the flesh 

 of animals in which the disease is just beginning, or in which it is 

 restricted to one or more related organs, is not rejected. When, 

 however, the disease has affected the muscles or bones, or lymphatic 

 glands situated on or between them, the flesh is condemned as unfit 

 and dangerous. Animals are also rejected in which it is evident, 

 from the general distribution of tubercles throughout the various 

 organs, that the bacilli have been distributed by the blood and may 

 have been carried into the muscular system (generalized tuberculosis). 



Concerning the infectious nature of milk secreted by tuberculous 

 cows, authorities have imiversally agreed that when the udder itself 

 is in the slightest degree involved the milk possesses infectious prop- 

 erties, and is therefore dangerous. Tubercle bacilli in large numbers 

 have been found in the milk and the udder under such circumstances. 

 Unlike other affections of the udder, tuberculosis of this organ does 

 not at once change the appearance and the quality of the milk 

 secreted. Bang states that for at least a month after the disease has 

 appeared the milk is normal in appearance and may be consumed 

 and sold without arousing the suspicion of the owner. Considerable 

 danger is, therefore, involved in this disease, and the necessity for 

 the careful inspection of dairy cows seems more urgent than ever. 



Authorities are, however, not fully agreed as to whether the milk 

 from tuberculous cows in which the udder is apparently not invaded 

 by the disease should be considered dangerous or not. Some incline 

 to the belief that the milk secreted by healthy udders is never infec- 

 tious, even when the lungs or other organs are affected ; that, in other 

 words, the tubercle bacilli are rarely, if ever, separated from the 

 lesions which they produce, and that the udder itself must be diseased 

 before tubercle bacilli can appear in the milk. Experiments made 



