FIG. 18. Diagram to illustrate the life-history of the human tertian parasite, Plas- 

 modium vivax. (After Liihe, from Braun.) Magnification : 117, 1,200 : 1. 1827, 600 : 1. 

 7, Sporozoite. 2, Penetration of the sporozoite into a red blood cell. 3 4, Growth of the 



