8o FOWL CHOLERA 



blood vessels engorged. The gall bladder is distended with 

 thick dark bile. 



The crop is usually distended with food, though no 

 special lesions have been noticed here. The stomach viewed 

 externally, often presents a number of circular discolorations 

 about three millimeters in diameter, which on section are 

 found to be extravasated blood. The small intestines are 

 congested. 



The rectum and cloaca usually present deep red lines 

 upon their mucous membrane, evidently' the first stage of 

 inflammation, which results, in chronic cases, in thickening 

 of the walls, especially of the rectum, the desquamation of the 

 mucous membrane, and the formation of large ulcerated 

 surfaces. 



The mesentery is generally congested, often greatly 

 thickened and reddened, and rendered opaque by inflamma- 

 tion. The ureters are distended with yellow urates ; the 

 kidneys seem engorged, and on section accumulations of the 

 tenacious, yellow urates are frequently seen. The spleen is 

 generally normal in size and appearance, though frequently 

 enlarged and softened. 



The pericardium is sometimes distended with effusions, in 

 which case there is noticeable hyperaemia of the surface of the 

 heart. The lungs are often, though not generally, engorged 

 with dark blood ; they are seldom, if ever, hepatized. 



The blood vessels are sometimes filled with a firm clot, 

 and contain but little liquid ; at other times the blood does 

 not coagulate at all. It seems to be those cases in which the 

 duration of the disease is longest, that the blood loses its 

 power to coagulate. 



§ 69. Differential diagnosis. Fowl cholera is to be 

 differentiated (i) from a number of dietary disorders which 

 cause the death of a large number of fowls. These cases are 

 often thought to be chicken cholera and so reported by the 

 owners. A diagnosis is to be made in the findings of a bac- 

 teriological examination. (2) Fowl cholera is to be differ- 

 entiated from infectious leukaemia. There are a number of 

 resemblances in the clinical history of the two diseases but 



