28l 



round chromatin mass, and the protoplasm projects as a 

 circlet of rays (i). Forms occur in which two club- 

 shaped parasites have stuck together in their long axis 

 or ' copulated ' (2). All these rays are eventually 

 withdrawn, and from the second to third day spherical 

 forms of increased volume occur (3). 



On the third day structures appear whose relation- 

 ship to the previous forms is at present unknown. They 



Fig. 91 Development of P. bigeminum according to Koch 



consist of immense numbers of amoeba-like piroplasma 

 forms, surrounding a large nucleus possibly that of 

 a body cell (4). The chromatin in these parasites 

 consists of scattered granules. The parasites separate 

 from the heaps and grow, and the chromatin con- 

 denses. They now have a characteristic club shape (5). 

 These forms are seen also in the eggs of ticks. The 

 developmental cycle has not been further traced by 

 Koch, but cp. P. canis. 



2. P. parvum. Is found in cattle on the East 

 coast of Africa, etc., and a similar, if not identical, 



