INFECTIOUS DISEASES OF CATTLE. 403 



coalescence of many tubercles and the secondary formation of the same. 

 These may be found on the lungs, the ribs, and the diaphragm. These 

 tubercles likewise undergo degenerative changes. The center partly 

 soft ens, partly calcines into a grayish mortar-like mass, and when cut into 

 they are found to be gritty. Associated with the formation of tubercles 

 on the pleura, those glands situated back of the lungs (posterior medias- 

 tinal) become greatly enlarged and the center cheesy. (Plate xxxvi.) 

 They may compress the esophagus and interfere with swallowing. 

 The size attained by these tumors and new growths is well illustrated 

 by the fact that, taken together, they not infrequently weigh from GO to 

 80 pounds. The bronchial glands, which in the healthy state are not 

 a< large as horse-chestnuts, have been found to attain a weight of over 

 10 pounds. 



In the abdominal cavity tubercles may be found, both in the organs 

 and on the serous membranes covering them. They are situated pref- 

 erably on the oinentum or caul (see Plates xxxvn, XXXYIII, Fig. 2), the 

 diaphragm, and the walls of the abdomen. In the liver large and small 

 tubercular masses are occasionally encountered. (See Plate xxxv.) 

 The mesenteric glands (see Plate xxxvni, Fig. 1) are occasionally en- 

 larged and tuberculous; likewise the glands near the liver. Tubercles 

 may also develop in the spleen, the kidneys, the uterus and ovaries, and 

 the testicles. 



Tubercular a flection of the intestines seems to be quite rare, although 

 ulc.-rs ut' the large intestines have been observed. Nodules may also 

 form under the serous covering of the intestines. 



The brain and spinal cord are occasionally found tuberculous. Of 

 40 cases, Scinmer found tuberculosis of the brain in 4. It is not 

 improbable that, owing to the infrequency of exposing the brain and 

 spinal cord, tuberculosis may have escaped the attention of patholo- 

 gist*, and it may be that it is not so uncommon as is generally supposed. 

 The tubercles occur on the membranes of the brain as well as in the 

 subst ance of the brain itself. They project into the ventricles as masses 

 varying in sixe from a pin's head to a hen's egg. They finally lead to 

 various inflammatory changes. Johne has observed numerous small 

 tubercles on the membranes of the spinal cord. 



Y<TV rarely tuberculous lesions have been observed in the bones and 



muselrs of the body. Not so rare, however, is the aftectioii of the 



lymphatic glands imbedded in the muscular tissue and those which can 



be idt l>eneath the skin. These are situated at the joints, under the 



and along the neck. 



Tubercular disease of the udder in cows has received considerable 

 attention of late from sanitarians, owing to the infection of the milk 

 wit h the virus of tuberculosis. According to those who have given this 

 eet special attention the udder becomes swollen uniformly and 

 quite linn. This swelling, which is painless, frequently attacks but one 

 qnarN'r. more rarely two. these being usually the hind quarters. The 

 larger milk ducts contain yellowish cheesy particles, in which are many 



