MORBID ANATOMY 375 



animals one finds edema of the lungs with blood stained muco- 

 serous substance in the trachea and bronchioles. The 

 lymphatic glands are rarely if ever altered in appearance. 



The central nervous system presents nothing of note, 

 except a slight congestion of the meninges. 



The histological study of the lesions shows that the tissue 

 changes start from greatly engorged capillaries. In these 

 vessels containing masses of blood, a large part of the red cor- 

 puscles contains the parasite. 



The histological examination of the organs when hardened 

 in Miiller's fluid shows, according to Graham-Smith, the capil- 

 laries of the alveoli of the lungs to be dilated and in some 

 instances a proliferation of the lining cells some of which are 

 seen lying free in the air cells. In other alveoli the process is 

 more advanced and proliferated cells, leucocytes, and in some 

 cases red corpuscles are present in them. The lumen of many 

 of the bronchioles frequently contains desquamated epithelium, 

 leucocytes and mucus. There is no evidence of any increase 

 in the connective tissue. No pigmentary or fatty changes were 

 observed in the heart or skeletal mu.scles. The liver showed 

 the most marked changes. The central vein of the lobule and 

 the capillaries lying between the liver cells were dilated. The 

 protoplasm of the liver cells stains feebly but the nuclei take 

 the stain fairly well. The cells are distorted between the 

 dilated blood vessels and in many cases almost destroyed, 

 especially those in the central zone. The vessels in the inter- 

 lobular spaces are dilated but the bile ducts are normal. There 

 is no increase of fibrous tissue and the capsule is normal. The 

 capillaries contain a large number of red blood corpuscles and 

 the proportion of leucocytes is high. The latter are also very 

 numerous in the larger vessels. In these vessels about 10% 

 of the red corpuscles are infected. The para.sites usually appear 

 in small groups in the cells. The proportion of leucocytes to 

 red corpuscles is about i to 10. In the capillaries from 23 to 

 53% of the red corpuscles are infected and in some in.stances 

 the proportion of leucocytes to red corpu.scles is as high as r 

 to 3. In but one dog did he find fatty changes. The smear 



