528 



Malaria 



Parasite. Disease. 



Plasmodium fal- Aestivo - autum- 

 ciparum nal fever. 



Plasmodium 



kochi. 

 Plasmodium 



inui. 



Plasmodium 

 pitheci. 



Plasmodium 



brazilianum. 

 Plasmodium 



cynomolgi. 



Plasmodium 

 grassii (Pro- 

 teosoma gras- 

 sii). 



Plasmodium 

 danliewskyi 

 (Halteridium 

 danliewskyi) . 



Host. 



Man. 



Cercopithicus. 



Macacus (In- 

 uus cyno- 

 molgus). 



Orang - outang 

 (Pithecus sa- 

 tyrus) . 



Brachyrus cal- 

 ores. 



Inuus cynomol- 

 gus and Inuus 

 nemistrinus. 



Sparrows, can- 

 ary birds, and 

 other small 

 birds. 



Owls, hawks, 

 crows, and 

 other large 

 birds. 



Insect host. 



Anopheles, My- 

 zorrhynchus, 

 Myzomyia. 



Unknown. 



Unknown. 



Unknown. 



Unknown. 

 Unknown. 



Culex pipens. 

 Unknown. 



These micro-organisms correspond in all essentials. They 

 are protozoan parasites belonging to the sporozoa and live 

 in the blood (hematozoa) as parasites of the red corpuscles. 

 They all have two life cycles, one which is asexual in the 

 intermediate warm-blooded host, and one that is sexual in 

 the definitive cold-blooded (insect) host. Though the inter- 

 mediate hosts vary and may be birds or mammals, the 

 insect hosts, so far as known, are always mosquitoes. The 

 mosquitoes become infected by biting and sucking the 

 blood of infected animals; the warm-blooded animals be- 

 come infected by being bitten by infected mosquitoes, and so 

 on, in endless cycles. 



The parasites differ but little in the details of structure 

 and development, so that the following description may serve 

 as a type for all : 



From the proboscis of the mosquito, with its saliva, from 

 cells in the salivary glands where they have been harbored, 

 tiny elongate spindles, measuring about 1.5 ^ in length and 

 0.2 fi in breadth, and know as sporozoits, enter the blood of 

 the individual bitten. These sporozoits attach themselves 

 to the red blood-corpuscles, gradually lose their elongate 

 form, and become irregularly spherical. There is some 

 difference of opinion as to whether the little bodies are simply 

 upon the corpuscles, as Koch believed, or in the corpuscles, 



