PROTOZOA IN THE CIRCULATORY SYSTEM 89 



Ganietocytes 



Young ganietocvtes which originate in ring forms are 

 difficult to identify, but thev are less amoeboid, and more 

 rounded. Mature ganietocytes can easily be identified. 

 Thev mav appear during earh^ phase of the malarial at- 

 tacks. The development of ring forms to mature ganieto- 

 cvtes has been estimated as requiring some four days. 

 Thev are smoothlv rounded and occupy almost the whole of 

 the enlarged erythrocytes which may show Schiiffner's 

 dots. Brown haemozoin granules are numerous. The dif- 

 ferences between the mature macro- and micro-gameto- 

 cvtes are as follows: 



M acrogametocy tes Microgametocy tes 



(Fig. 22, 11) (Fig. 22, 12) 



Size Large, 9-10 |.i in diameter Small, 7-8li in diameter 



Cytoplasm Stains more deeply Stains less deeply 



Nucleus Compact and smaller. Large, composed of many 



staining dark red chromatin granules 



which stain less deeply 



No further change takes place in human ery throe vtes. 

 If fresh blood containing microgametocvtes, is kept at 

 room temperature on a slide under a sealed cover-glass, 

 formation of microgametes mav be seen. 



2. Plasmodium mnlariae (Laveran 1881) 



This species is the cause of the quartan malaria in which 

 the attacks of fever occur at intervals of 72 hours or ever\' 

 fourth dav which is the time necessary for completion of 

 schizogonic cycle. It is distributed in the tropics and sub- 

 tropics, though it is the rarest of the three common species 

 of malarial parasites. As a rule in an area where all three 

 species of Plasmodium occur, Plasmodium malariae seems 



