THE MALARIA PARASITES 43 



dition, each spherical element provided with a nucleolus and the 

 eight or ten elements arranged so as to give the appearance of a 

 daisy. 



e. Find a corpuscle that has been broken down, thus liberating 

 the sporulated parasite. 



Draw several stages. 



B. Sporozoan of benign tertian malaria, Plasmodium vivax. 

 Examine blood slides from cases of tertian infection (malaria 



with fever recurring every two days, 48 hours). 



a. Note the fact that the pigmented granules of this parasite 

 are considerably finer than in the quartan. 



b. Signet rings as in A. 



c. In the segmentation stage of this form note the irregularity 

 in arrangement of the elements and their greater number. 



Draw several stages. 



C. Sporozoan of malignant tertian fever, Plasmodium pracox. 

 In a slide taken from an advanced case of malignant tertian 



malaria (aestivo-autumnal fever) note the presence of: 



a. Crescent-shaped bodies either free or intracorpuscular 

 (usually only one in a red corpuscle). The crescent stage in this 

 variety of parasite represents a condition just previous to the 

 sexual changes undergone in the body of the Anopheles mos- 

 quito, or on contact with the air (see below). Female crescents 

 have the chromatin massed centrally while the male crescents 

 have it distributed and are hyaline. 



b. The parasite of malignant tertian malaria (Plasmodium 

 pracox) is said to be smaller in the mature form than is the 

 benign tertian parasite. 



c. Examine signet rings for double nuclei. 

 Draw crescents. 



D. The stained parasites of malaria often show ring forms, 

 and when stained with Romanowsky stain, the red nucleus may 

 be between the ends of the slender crescent, forming thus a 

 " signet ring" 



a. Examine slides for the "signet ring" forms. 



