SPOROZOA 



439 



center, giving the parasite the appearance of a signet ring, the 

 setting beings represented by the nucleus or chromatin granule 



Fig. 199. — Plasmodium falciparum, forms in the asexual cycle (schizogony). 

 A , Multiple infection of an erythrocyte, showing signet rings and parasites attached 

 to the external surface. B and C, Growing parasites with Mauer's granules in the 

 erythrocytes. D, Growing parasite without granulation of the hemoglobin. E, 

 Half-grown parasite showing pigment. F, and G, Multiple division (sporulation) , 

 rarely seen in the peripheral blood. {After Dojlein.) 



which stains violet red with the Romanowsky stains. The 

 parasite attains a diameter of about 6/^, when it segments to 

 produce 7 to 16 merozoits or 

 agametes which enter new ery- 

 throcytes and repeat the cycle. 

 The larger stages of this cycle of 

 schizogony are rarely seen in the 

 peripheral circulation, and the 

 segmentation of the parasite oc- 

 curs in the capillaries of the in- 

 ternal organs. The cycle prob- 

 ably requires 48 hours for its 

 completion. The erythrocyte 



is not enlarged by the growth of the parasite within it but tends 

 rather to become smaller. Maurer has observed an irregular 



Fig. 200.— Section through a capil- 

 lary in the brain, showing^numerous di- 

 viding forms of the non-pigmented type 

 of PI. "■• falciparuih. (Stained prepara-^ 

 tion.) {From, Doflein after Mannaberg.) 



