Life-cycle of the tertian parasite {Plasmodiuin vivax.) Figs, i to 17, X 1,200; figs. 18 to 27, X 600. (After 

 Liihe, based on figures by i-chaudinn and Grassi.) i, sporozoite : 2, entrance of the sporozoite intoa red-blood 

 corpuscle ; 3, 4, growth of the parasite, now sometimes called a trophozoite; 5, 6, nuclear division in schizont ; 

 7, free merozoites ; 8, the nierozoites which have developed making their way into blood corpuscles, (arrow pointing 

 to the Ielt)and increase by schizogony (3— 7) ; after some duration of disease the se.\iial individuals appear ; ga— 12a, 

 macrogametocytes ; gft — 12/^ micvogametocytes, both still in the blood-vessels of man. If macrogametocytes (12a) 

 do not get into the intestine of Anopheles they may perhaps increase parthenogenetically according to Schaudinn 

 (i2rt ; 13c— 17c). The merozoites which ha^e arisen (17c) become schizonts 3—7. _ The phases shown underneath the 

 dotted line (13—17) proceed in the stomach of Anopheles. i^l> and I4<5, formation of microgametes ; i3rt and 14a, 

 maturation of the macrogametes ; 15/', microgamete ; 16, fertilization ; 17, ookinete; 18, ookinete in the walls of the 

 stomach; 19, penetration of the epithelium of ihe stomach; 20—25, stages of sporogony on the outer suiface of the 

 intestinal wall ; 26, migration of the sporozoites to the salivary gland ; 27, salivary gland with sporozoites. 



