442 . SPECIFIC MICRO-ORGANISMS 



the salivary glands, from which they escape into the human host 

 when the mosquito bites. The cycle in Anopheles requires eight 

 days at a temperature of 28° to ^o" C. At temperatures below 

 17° C. the microgametes are not produced. 



Development of the estivo-autumnal parasite through the 

 stages of schizogony has been obtained by Bass and Johns^ in the 

 test-tube, in a medium consisting of defibrmated blood to which 

 0.5 per cent-glucose has been added. They were able to keep the 

 organisms alive for ten days at a temperature of 40" C, during 



^4 



Fig. 205. — Section through salivary gland of Anopheles showing numerous 

 sporozoits of Plasmodium falciparum. I, Fat bodies; 2, gland duct; 3, sporozoits of 

 Plasmodium; 4, Secretion in the gland cells. (From Doflein after Grassi.) 



which period the developmental cycle was repeated four or five 

 times. Their findings have been confirmed by other investi- 

 gators. More recently Joukofi^ has reported partial development 

 in the test-tube, of the cycle of sporogony in the case of PI. falci- 

 parum, and greater success with PI. malaria. 



Plasmodixun Vivax.— The parasite of tertian malaria is dis- 

 tinctly different from the estivo-autumnal parasite. The young 

 merozoit is i to 2/i in diameter and practically not to be distin- 



1 Jomn. Exp. Med., 1912, Vol. XVI, pp. 567-579. 



^ Compt. Rend. Soc. Biol., 1913, Vol. LXXIV, pp.''i36-i38. 



