MALARIA 



209 



characterized by intermittent chills, fever, and sweats, 

 with prostration and progressive anemia. It is com- 

 mon in lowlands, where stagnant water collects, or 

 in the vicinity of slowly moving water, permitting the 

 propagation of mosquitoes. It is not communicable 

 by contact of man to man. It is the infestation of 

 the red blood cells by a parasite having three forms, 

 belonging to the order Hemosporidia. The parasites 

 are called the Plasmodium malaria, the P. vivax, and 



Some of the principal forms assumed by the plasmodium of tertian fever in 

 the course of its cycle of development. (After Thayer and Hewetson.) 



the P. falciparum. Three types of attack corre- 

 spond to the three protozoal species: (1) That which 

 gives chills and fever every third day, the tertian 

 malaria; (2) one where the paroxysm appears every 

 fourth day, the quartan type; and (3) a continuous, 

 typhoid-like type, the malignant or sestivo-autumnal 

 fever. 



The species vary in finer morphological details, but 

 they follow the same course in their transmission 

 14 



