FORMS OF THE MALARIAL PARASITE 527 



envelope of the red corpuscle. The pigment also becomes free 

 and may be taken up by leucocytes. The number and arrange- 

 ment of the spores within the sporocyte vary in the different 

 types. In the quartan there are 6-12, and the segmentation is 

 in a radiate manner, giving rise to the characteristic daisy-head 

 appearance; in the tertian they number 15-20 or more, and 

 have a somewhat rosette-like arrangement (Fig. 158) ; in the 

 malignant there are usually 6-12 spores of small size and 

 somewhat irregularly arranged. 



Gametocytes. As stated above, these are sexual cells which 

 are formed from certain of the amcebulae, and which undergo 

 no further development in the human subject. In the mild 

 tertian and quartan fevers they are rounded and resemble some- 

 what the largest amcebulae. The female cells, macrogametocytes, 

 are of large size, measuring up to 1 6 ft in diameter ; they con- 

 tain coarse grains of pigment, and the protoplasm stains somewhat 

 deeply with methylene-blue. The male cells, microgametocytes, 

 are smaller, and the protoplasm stains faintly ; the nucleus, 

 generally in the centre, is rich in chromatin. In the malignant 

 fevers the gametocytes have the special crescentic form mentioned 

 above. They measure 8-9 ^ in length, and occasionally a fine 

 curved line is seen joining the extremities on the concave aspect, 

 which represents the envelope of the red corpuscle (Fig. 161). 

 They are colourless and transparent, and are enclosed by a 

 distinct membrane ; in the central part there is a collection of 

 pigment and granules of chromatin. It is stated that the male 

 crescents can be distinguished from the female by their appear- 

 ance. In the former the pigment is less dark and more scattered 

 through the cell, and there are several granules of chromatin ; 

 in the latter the pigment is dark and concentrated, often in a 

 small ring, and there are one or two masses of chromatin in the 

 centre of the crescent. According to the Italian observers the 

 early forms of the crescents are somewhat fusiform in shape and 

 are produced in the bone-marrow. The fully developed crescents 

 do not appear in the blood till several days after the onset of 

 the fever, and they may be found a considerable time after the 

 disappearance of the pyrexial attacks. They are also little, if at 

 all, influenced by the administration of quinine. 



It is well known that after a patient has apparently recovered 

 from malarial fever a relapse may take place without fresh 

 infection occurring, and Schaudinn has published interesting 

 observations bearing on this point. He has found that the 

 macrogametocyte of tertian fever may by a process of partheno- 

 genesis give rise to merozoites, which in their turn infect the red 



