208 



AVIAN TUBERCULOSIS 



the surrounding tissue. The removed, necrotic nodules have 

 a roughened surface. The color is greyish or whitish in the 

 early stages, but in the later ones it changes to a yellowish 

 tint. Occasionally there are two distinct crops of tubercles, 



one consisting of no- 

 dules 4 to 6 milli- 

 meters in diameter 

 and separated by a 

 centimeter or more, 

 and the other of close- 

 ly set grayish tuber- 

 cles 0.25 to 0.5 mm. 

 in diameter. In some 

 cases the tubercles 

 are few in number 

 but larger i n size. 

 The liver cells be- 

 tween the tubercles 

 are usually in a state 

 of more or less degen- 

 eration, and frequent- 

 I3' fat globules are 

 numerous. The 

 blood spaces are more 

 than normally dis- 

 tended with blood. 

 The lesions in the spleen, like those in the liver, consist of 

 minute or larger tubercles of a grayish or of a yellowish tint. 

 The central portions of the larger tubercles are often homo- 

 geneous, darker in color and more or less hyaline in appear- 

 ance and consistency. 



The tubercular growths in the intestine start in the walls 

 of the intestine. They present a glistening appearance, gray- 

 ish in color and firm to the touch. Frequently they are 

 confluent. When single they vary from i to 10 mm. in 

 diameter. They are usually sessile on the intestine but on 

 the mesentery they are frequently pedunculated, varying from 



Fig. 47- 



A photograph of a tuberculous 

 liver from a fowl. 



