268 SPOROZOA. 



Aragao (1930) has studied the development of the gameto- 

 cytes of Laverania malar im, and finds that there are two 

 types of merozoites, corresponding to the male and the female 

 gametocytes. Merozoites destined to form male gametocytes 

 after entering a corpuscle are spherical with a distinct nucleus 

 and without the vacuole typical of ring forms, while those 

 destined to give rise to female gametocytes stretch across the 

 corpuscle in the form of an elongate bar. 



Knowles and Das-Gupta (1931) observed scanty phago- 

 cytosis in a case of infection with L. malarias, and Chopra, 

 Das-Gupta, and Sen (1932) observed heavy phagocytosis of 

 parasites by the polymorphonuclear and large hyahne leuco- 

 cytes in another case. Stott (1933) has reviewed the previous 

 hterature on the phagocytosis of malarial parasites and 

 recorded his own observations in two cases. In severe 

 malignant tertian infection approximately 50 per cent, of 

 red blood-cells may be infected, and in such cases merozoite 

 formation may be seen in the peripheral circulation. Large 

 mononuclear cells may show their phagocytic power, even in 

 the peripheral circulation of severe cases, by the presence of 

 (1) pigment, (2) rings, (3) red cells, normal or dehsemoglobi- 

 nized, and non-infected or infected with sporulating or, less 

 commonly, with other forms of malarial parasites. 



MissiroH (1933), working with Culex fatigans infected with 

 bird malaria, and Knowles and Basu (1935) with Anopheles 

 stephensi infected with Laverania malariee and Plasmodium 

 vivax, have observed division of the nucleus of the sporozoites 

 into two, three or more parts. The sporozoite is then said to 

 divide into a corresponding number of small rounded bodies 

 consisting almost entirely of chromatin with scarcely any 

 visible cytoplasm. These apply themselves to the surface 

 of the red corpuscles and presumably grow into the usual ring- 

 trophozoite forms. If these observations are confirmed it 

 would mean that the sporozoite is not the end of the sporogony 

 cycle, but that occasionally, at any rate, it breaks up into 

 smaller bodies which, after entering the corpuscles, grow into 

 trophozoites. 



ChaouHtch (1936) has recently observed that asexual 

 multiphcation can also take place by binary fission of the 

 schizont. 



Alessandrini (1933) reported a new method of reproduction 

 for L. malarise, i. e., simple amitotic division, occurring both 

 in man and mosquito, but only when the resistance of the host 

 is distinctly lowered by infection, adverse environmental 

 influences, etc. This amitotic reproduction results in a more 

 rapid and virulent multiplication of the parasite, accounting 

 for the occasional pernicious character of the disease. Hingst 

 (1934) has also adduced evidence to show that in some indi- 



