MALARIA 127 



Although it is possible, experimentally, to produce 

 malaria by inoculating a person with blood from a 

 patient suffering from the disease, yet, in practice, 

 malaria can never be transmitted without the aid of 

 the particular mosquitos mentioned. In other words, 

 without mosquitos there can be no spread of malaria. 



There are three recognized types of the hemameba 

 the quartan, the tertian, and the estivo-autumnal 

 parasite. The two former cause a relatively benign 

 infection, while the estivo-autumnal parasite causes 

 malignant malaria. (Plate II.) 



The organism of the quartan malaria develops in the 

 blood in seventy-two hours; hence, there is a febrile 

 stage every third day. Under the microscope, in a 

 fresh smear, the organism is a tiny refractive body, 

 slightly motile, and contains coarse, blackish-brown 

 pigment. It segments into six to twelve round amebulse. 



The tertian parasite is less glistening, but more ac- 

 tively motile than the quartan; its cycle in the human 

 host is completed in forty-eight hours, and it then 

 divides into fifteen to twenty oval bodies. The pigment 

 of the tertian parasite is yellowish brown and quite fine. 



Estivo-autumnal parasites are small and show more 

 active ameboid motion than the other two; they contain 

 very little pigment, which is dark and quite fine. The 

 red blood-corpuscles which contain the parasite are apt 

 to shrink and assume a brassy color. This type com- 

 pletes its cycle chiefly in the blood of the internal organs 

 (e. g., the spleen), and it may be difficult to locate it at 

 all in the circulation. Its sexual forms are crescentic in 

 shape. All three types are best stained with methylene- 

 blue. The Romanowsky method uses a compound ob- 



