The Human Malarial Parasites 



509 



there are no regularly occurring paroxysms. The duration of the 

 asexual cycle is from twenty-four to forty-eight hours. 



The gametocytes are striking and characteristic oviod and cres- 

 centic bodies^ — crescents — 1}4 times the diameter of a red blood- 

 corpuscle in length, and about half the diameter of the corpuscle 



©O £' IT o 



Fig. 1^7. — Parasite of estivo-autumnal fever: a, b, c, Ring-like and cross- 

 like hyaline forms; d, e, pigmented forms;/, g, segmentary forms; h, i,j, crescents. 



in breadth. The ends color more intensely with methylene blue 

 than the middle portion, and the bacillary pigment granules are 

 collected toward the centers. The longer and more slender crescents 

 are usually bent, and the relic of the corpuscle in which they have 

 formed can often be seen forming a line connecting the ends on the 

 concave side. These are the microgametocytes or male elements. 



Fig. 188. Fig. 18 



Figs. 188, 189. — Gametocytes of Plasmodium falciparum: 91, The microga- 

 metocyte; 92, the macrogametocyte (KoUe and Wassermann). 



The macrogametocytes are broader, not curved, and sometimes 

 are ovoidal or prolate spheriodal in shape. The pigment granules 

 are more widely scattered throughout the substance. The cres- 

 cents are most numerous after the fever has lasted for some time or 

 in recurrences of the fever. The life duration of a crescent is about 

 three weeks. 

 The fever in this form of malarial infection may be intermittent 



