280 



THE PATHOGENIC HEMOSPORIDIA 



(for bird malaria) and anopheles (for human malaria) are alone capable 

 of transmitting the disease from host to host. Little by little new facts 

 and discoveries were added, until by 1901 malaria was as thoroughly 

 understood as perhaps any other germ disease, Grassi, in Italy, working 

 out the complete life history of the pernicious type, and Schaudinn, 

 in 1901, the life history of the parasite causing the tertian form of the 

 disease; the latter adding the last link in the chain of evidence by 

 watching the penetration of the sporozoite fresh from a mosquito's 



FIG. 109 



Temperature variations in tertian malarial fever. 

 FIG. 110 



Temperature variations in quartan malarial fever. 



proboscis in his own red blood corpuscles. Malaria was thus the first 

 of the human diseases in which it was proved that a protozoon is the 

 direct cause. 



Authorities differ as to the number of kinds of these protozoan para- 

 sites responsible for malaria. On the clinical side, also, there seems 

 to be some difficulty in the classification of the fevers due to the dif- 

 ferent kinds of parasites. Grassi and Laveran have reduced the large 

 number of species that have been described to three, and they believe, 



