354 



TEXAS FEVER 



Fig. 91. Blood from 

 kidney shoicing para- 

 sites of Texas fever 

 [Smith). 



toxylin. As a rule they stain more deeply in preparations 

 made from internal organs than they do in tljose from the 

 living blood. 



In the capillaries of the congested organs, the blood cor- 

 puscles contain many more parasites. 

 Smith has noted in one case from 2 to 3 

 per cent of infected corpuscles in the 

 circulating blood but in cover- glass prep- 

 arations made at the autopsy quite 

 different results were obtained. In those 

 from the skeletal muscles, blood of the 

 right heart, and blood from the bone 

 marrow (sixth rib) very few infected 

 corpuscles were found ; in the blood 

 from the left heart and lung tissue from 

 2 to 3 per cent of infected corpuscles ; in 

 the spleen 5 per cent ; in the liver and 

 kidney tissue from 10 to 20 per cent ; 



and in the hyperemic fringes of the omentum and the heart 



muscle 50 per cent of the corpuscles 



were infected. In other cases the 



blood corpuscles in the capillaries 



were more and in still others less 



extensively infected. In the living 



blood the parasites were pyriform, but 



in the post-mortem specimens they C^^ 



were more nearly round. In the mild 



type of the disease from 5 to 50 per 



cent of the red corpuscles in the circu- 

 lation are infected for a period of from 



one to five weeks. The parasite is 



round (coccus form). In the fresh 



preparations it is seldom seen ; rarely 



it can be detected as a pale spot about 



o.5/< in diameter at the periphery of 



the corpuscle. In stained (alkaline methylene blue) prepara- 

 tions, the parasites appear as round coccus-Hke bodies from 



Fig. 92. Cover-glass prep 

 aration from k id ney . Cor- 

 puscles shoiving Piroplas- 

 ma, coccus form (Smith). 



