748 MUltlEJ. iiOJJKRTSON. 



in a blood-corpuscle, but is apparently lying free in a capillary 

 of the lung. The schizont now increases immensely in size, 

 and the nucleus multiplies by successive divisions. The 

 mitosis is of a very simple type ; the amount of chromatin 

 seems to augment by division of the granules, the nucleus 

 becomes slightly elongated, the central body divides, and the 

 strand of staining material which connects them appears to 

 play the role of a simple spindle. The chromatin granules 

 now become loosely grouped about each new central body, 

 and the connecting strand disappears. From the scarcity of 

 division-figures one is inclined to think that this primitive 

 mitosis must take place very rapidly (figs. 16, 21). 



During these processes of growth and nuclear multiplica- 

 tion the shape of the body is maintained, and there results a 

 very large bean-shaped or sausage-shaped organism sur- 

 rounded by a membrane. It is circular in section (figs. 

 21—23), and contains a large number of nuclei ; I have 

 counted about seventy, but the number appears to vary. A 

 point of some interest is that very little, if any, diminution 

 takes place in the size of the nuclei; it will be observed, also, 

 in the figures that they are evenly distributed through the 

 cell-body and not arranged at the periphery. 



The protoplastn finally segregates round the nuclei, and 

 there are formed a corresponding number of merozoites, 

 which still lie within the envelope. They are presently set 

 free as sausage-shaped hajmogregarines of 6 to 7"5/x in 

 length, that is to say, only little below the average size 

 (8 to 10 fxY of the heemogregarines seen in the blood. They 

 have usually rather regular nuclei of the rounded or slightly 

 elongated type. 



Schizogony in the Blood-corpuscle (figs. 10-16). — 

 In the blood of practically all the infected tortoises examined 

 multinucleate liEemogregarines were found in greater or less 

 numbers. These forms may show any number of nuclei up to 

 eight ; generally, however, they do not show more than six. 

 From a study of the early biuucleate phases it is clear that 

 these specimens arise from beau-shaped htemogregarines (figs. 



