Tuberculosis. 441 



and small tubercles, in all stages of degeneration are met with in 

 the enlarged liver, the spleen, pancreas, kidney, etc. 



Apes and Menagerie Animals. In these tuberculosis is com- 

 mon alike in the thoracic and abdominal forms, and the lesions in 

 the main are those of domestic cattle. 



Chickens. The lesions are common in the abdominal cavity, 

 the intestines, liver and spleen being the most frequently attacked, 

 while the subcutaneous connective tissue, bones and joints also 

 suffer. The lungs and kidneys usually escape. The intestinal 

 mucosa shows small nodules, often caseated, or ulcers ; the 

 enlarged and friable liver is studded with tubercles from the size 

 of a hemp seed upward, gray or translucid, homogeneous or with 

 central necrosis, simply or in conglomerate masses, with congested 

 or hsemorrhagic periphery ; the spleen is swollen and permeated 

 by similar deposits ; fibrinous ascitis is not uncommon ; the 

 abdominal lymph glands are enlarged and congested. 



The early tubercle shows a central, necrotic, hyaline area, con- 

 sisting of the debris of disintegrated cells, which is colored brown 

 by picro carmine, unlike the nucleus of the pheasant tubercle 

 (Cadiot). Around the hyaline centre is a zone of large epithe- 

 lioid cells, the nuclei of which stain strongly in carmine. Out- 

 side this is the usual zone of small, round, lymphoid cells. In 

 the whole the tubercle bacilli can be made manifest by the carbol- 

 fuchsin (Ziehl-Neelsen) stain. In the older and larger tubercles 

 the central necrotic mass has encroached in part or in whole on 

 the epithelio-lymphoid zone. 



Pheasant. The lesions have the same seats and naked-eye 

 aspect as the chicken tubercle, but under the microscope the 

 smallest and most recent tubercles show epithelioid cells to the 

 centre, or later, the central zone presents a dense fibrous network 

 enclosing open spaces and giving a mahogany stain with L,ugol's 

 solution (iodine and potassium iodide). (Cadiot). There has 

 been an organisation of connective tissue which has submitted to 

 amyloid degeneration, making a clear distinction from the tubercle 

 of chicken. 



Parrot. The lesions were thus located by Eberlein and Cadiot: 



