i68 



THE ANIMAL PARASITES OF MAN 



darker than the normal (brass-coloured). In the early stage dots or 

 stippling sometimes called Maurer's dots appear on the blood cor- 

 puscles as in those attacked by the ordinary tertian parasite (Plasmo- 

 dium rirax), but the Maurer's dots are relatively coarse and few, and 

 are not easily stained. These dots were first described by Stephens 

 and Christophers in 1900, and subsequently by Maurer in 1902. 



About thirty hours after the entrance into the blood corpuscles, 

 the parasites are rarely found in the peripheral blood, but they are 

 present in the internal organs, and especially in the spleen. The 

 schizogony, which now begins in the internal organs, proceeds on the 

 same lines as that of the quartan parasite, that is, usually with the 

 merozoites radially arranged around a central agglomeration of dark 

 brown pigment. 



a 



O 



m 



^ 



FIG. 87. The pernicious malignant or sub-tertian parasite in the red corpuscles of man, 

 asexual stages. (After Manson.) 



The number of merozoites formed is quoted differently, e.g., 8 to 24, 

 on an average 12 to 16. However, according to the recent cultural 

 researches of J. G. and D.Thomson 1 (1913) the number of merozoites 

 of P. falcipanun is 32. D. Thomson, from examination of spleen 

 smears at autopsy, also concludes that the number of merozoites may 

 reach 32. During their formation the blood corpuscle which is 

 attacked gets paler and disintegrates. 



FIG. 88. The crescents of the malignant tertian parasite. (After Mannaberg.) 



See also fig. 81. 



The gametocytes which finally appear are attenuated, curved 

 bodies, rounded at each end and known as crescents (figs. 81, 88), and 

 are provided with a nucleus and with coarse pigment masses. In the 

 males the pigment is more scattered than in the females, where it is 

 around the nucleus. Their length is 9 /j, to 14 //,, and their breadth is 



1 Proc. Roy, Soc., B, Ixxxvii, p. 77. 



