328 BACTERIOLOGY. 



animals present no marked symptoms ; exceptionally 

 somnolence and diarrhoea have been observed at this 

 period, indicating acute intoxication from which the 

 animal has recovered. The affection is unattended by 

 fever. The most marked symptom is loss of weight. 

 This is usually progressive from the first or second day 

 after inoculation, with slight fluctuations until death. 



At autopsy the animal is found to be emaciated. 

 The subcutaneous tissues and the muscles appear pale 

 and dry. The serous cavities, particularly the peri- 

 cardial, may contain some excess of serum. The viscera 

 are anaemic. The spleen is small, thin, and pale. Ex- 

 ceptionally ulcers and ecchymoses are observed in the 

 caecum, but generally there are no lesions of the intes- 

 tinal tract. 



The most striking and constant lesions, those most 

 characteristic of the affection, are in the bile and in the 

 liver ; the quantity of bile may not exceed the normal, 

 but in other cases the gall-bladder may be abnormally 

 distended with bile. The bile is nearly colorless or has 

 a pale yellowish or brownish tint, with little or none of 

 a greenish color. Its consistence is much less viscid 

 than normal, being often thin and watery. It usually 

 contains small, opaque, yellowish particles or clumps 

 which can be seen floating in it, even through the walls 

 of the gall-bladder. These clumps consist microscopi- 

 cally of bile-stained, apparently necrotic, epithelial 

 cells ; leucocytes in small numbers ; amorphous masses 

 of bile pigment, and bacteria often in zoogloaa-like 

 clumps. Similar material is found in the larger bile- 

 ducts. 



The liver frequently contains opaque, whitish or 

 yellowish-white spots and streaks of irregular size and 



