i8o SOME MINUTE ANIMAL PARASITES 



and ovoid bodies (Fig. 37, A ). Pyriform parasites 

 (Fig. 37, B) are not common. Irregular forms also 

 occur. 



Division is of the simple type (Fig. 37, E) and is 

 performed within the internal organs and especially 

 in the glands. Investigation in England has shown 



FIG. 37 THEILERIA PARVA FROM THE BLOOD OF A Cow : BLOOD- 

 CORPUSCLES REPRESENTED DIAGRAMMATICALLY 



A, Ovoid form of parasite with chromatin at one end ; B, pyriform 

 parasite ; C, club-shaped forms ; D, rodlike organisms, one 

 with two chromatin masses; E, corpuscle containing several 

 parasites, two of which have chromatin caps showing apparent 

 division ; F, corpuscle containing six different forms of 

 T. parva 



a remarkable constancy in the numbers of the 

 parasites in different organs of the cow, and of 

 similar relations between the different forms of 

 parasites found at one time. Infected blood-cells 

 containing four or more parasites (Fig. 37, E, F) 



