658 INFECTION AND IMMUNITY. 



eight to ten days. Such are the cells which are 

 inoculated into man by the bite of the mosquito. 

 The changes which they undergo before they ap- 

 pear as clear oval bodies in the erythrocytes are 

 unknown. 

 Parasite The asexual cycle of the quartan parasite is 



1 a F a e r ve" identical with that of the tertian, with the excep- 

 tion that seventy-two hours are required for its 

 completion. It contains more pigment, and when 

 division takes place eight, or at most fourteen, 

 young parasites are formed, in contrast to the 

 fifteen to twenty-five of the tertian parasites. The 

 erythrocytes do not become large and pale (Euge). 

 The sexual cells practically are indistinguishable 

 from those of the tertian parasite, although they 

 are, on the whole, slightly smaller. The sexual 

 cycle also is completed only in the body of the 

 female anopheles mosquito, and is identical with 

 that of the tertian parasite. 

 Parasite of The parasite of a3stivo-autumnal fever is from 



Autumnal one-half to two-thirds the size of the tertian para- 

 er ' site, a difference which is constant in the various 

 stages of development of the asexual cell. It 

 divides eventually into from eight to twenty-five 

 young parasites, the cycle occupying from twenty- 

 four to forty-eight hours. 



"Haif-Moon Here, as in quartan fever, the erythrocytes do 

 not become swollen and pale, but even appear 

 darker in color, because of some shrinking (Huge). 

 The sexual cells in aestivo-autumnal fever are 

 characteristic. Whereas they at first do not differ 

 in shape from the asexual cells, as they grow older 

 they gradually assume the shape of a half moon in 

 one edge of the erythrocyte, reaching a length 

 equal to one and one-half diameters of the red cell. 



