354 



TEXAS FEVER 



Fig. 91. Blood from 

 kidney showing para- 

 sites of Texas fever 

 {Smith) . 



toxylin. As a rule they stain more deeply in preparations 



made from internal organs than they do in those 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 

 ~-.y-^=^f Jl/ circulating blood but in cover-glass prep- 



"^^^-^^^ss^ 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 



were more nearly round. In the mild 



type of the disease from 5 to 50 per 



cent of the red corpuscles in the circti- 



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-like bodies from 



Fig. 92. Cover-glass prep 

 aration from kidney . Cor- 

 puscles showing Piroplas- 

 ma, coccus form {Smith). 



Digitized by Microsoft® 



