628 MALAEIAL FEVEK 



movement varies somewhat in different types of fever. As they 

 increase in size, pigment appears in their interior as minute dark 

 brown or black specks, and gradually becomes more abundant 

 (Figs. 175-177; Plate V., Fig. 21 c, d, e, Fig. 22 e). This 

 pigment is elaborated from the hasmoglobin of the red cor- 

 puscles, the parasite growing at the expense of the latter. 

 The red corpuscles thus invaded may remain unaltered in 

 appearance (quartan fever), may become swollen and pale 

 (tertian fever), or somewhat shrivelled and of darker tint 

 (malignant fever). In stained specimens a nucleus may be 

 seen in the parasite as a pale spot containing chromatin which 

 may be arranged as a single concentrated mass or as several 

 separated granules, the chromatin being coloured a deep red by 

 the Eomanowsky method. The protoplasm of the parasite, 

 which is coloured of varying depth of tint with methylene-blue, 

 shows great variation in configuration (Fig. 177). The young 

 parasites not infrequently present a " ring-form," a portion of 

 the red corpuscle being often enclosed by the parasite. These 

 ring-forms are met with in all the varieties of the parasite, but 

 they are especially common in the case of the malignant parasite, 

 where they are of smaller size and of more symmetrical form 

 than in the others (Fig. 181). 



Within the red corpuscles the parasites gradually increase 

 in size till the full adult form is reached (Fig. 178). In this 

 stage the parasite loses its amoeboid movement more or less 

 completely, has a somewhat rounded form, and contains a 

 considerable amount of pigment. In the malignant form it only 

 occupies a fraction of the red corpuscle. The adult parasites 

 may then undergo schizogony, but not all of them do so ; some 

 become degenerated .and ultimately break down. 



3. Sehizonts. — In the process of schizogony the nuclear 

 outline becomes lost, and the chromatin becomes divided into 

 a number of small granules which are scattered through the 

 protoplasm ; the latter then undergoes corresponding segmenta- 

 tion and the small merozoites or enhsemospores result. The 

 pigment during the process becomes aggregated in the centre 

 and is surrounded by a small quantity of residuary protoplasm. 

 (Schaudinn has found in the case of the tertian parasite that 

 schizogony begins by a sort of primitive mitosis, which is then 

 followed by simple multiple fission.) The merozoites are of 

 rounded or oval shape, as above described, and are set free 

 by the rupture of the envelope of the red corpuscles. The 

 pigment also becomes free and may be taken up by leucocytes. 

 The number and arrangement of the merozoites within the 



