THE PATHOGENIC HEMOSPORWIA 279 



phase, his evidence for which is scarcely convincing, then it should be 

 classed with the organism of kala azar (^Herpetomonas donovani) 

 rather than with babesia. 



C. The Organisms of Malaria. — As late as 1896 the cause of 

 malaria and of its mode of transmission were equally little known, 

 while the idea of bad air, from which malaria gets its name, has a 

 long traditional history reaching back to the time of Morton, in 1692 

 (Craig). The irregularity of infection, the curious sporadic nature of 

 new cases, and the general history of the disease in damp and swampy 

 localities, made malaria, in its several forms, a most uncertain and 

 puzzling disease, the actual cause of which was entirely unknown 

 until 1881, when a French military doctor in Algiers, Dr. Laveran, 

 discovered a new and curious organism in the blood of malaria victims, 

 which he characterized at once and without any misgivings as the cause 

 of the disease. At that time the blood-infesting sporozoa were very 

 little known, Lankester, indeed, having discovered, ten years before, 

 in 1871, a sporozoon in the blood of frogs and a form which he named 

 in 1882, calling it Drepanidium (Lankesterelld) ranarum. Laveran 

 did not recognize the possible relationship between the blood parasites 

 of the frog and man, parasites which, in 1885, Danilewsky grouped 

 together under the general name of hematozoa, which finally took the 

 form of the name hemosporidia, but regarded it as a plant organism 

 belonging to the genus oscillaria, and he named it Oscillaria malariae. 

 The curious interpretation of the organism as a vegetable possibly 

 owed its origin to the fact that the bacteria were being vigorously 

 studied at this period, for we find not only Laveran, but Metchni- 

 koff and Marchiafava and Celli, likewise giving to it a plant name. 

 The latter, in 1885, from its supposed resemblance to some of the 

 plasmodia-forming fungi, gave the malaria organisms the name of 

 Plasmodium malariae, while the former, two years later, named them 

 hematophyllum. Laveran's name being untenable, on the grounds 

 of mistaken genus, the next name suggested in chronological order 

 had to be accepted in conformity with the rules of zoological nomen- 

 clature, and thus it happens that a name which should be used only 

 to designate a condition assumed by certain kinds of organisms (fungi 

 and mycetozoa) has become a generic name. 



Laveran's discovery did not attract much attention; indeed, the 

 new organism as the cause of the disease was scarcely accepted by 

 pathologists, and it was not until after 1896 that the real nature of the 

 disease was recognized. Laveran ('91) in France, and Manson ('94) 

 in England, quite independently suggested that the organism is trans- 

 mitted from man to man by some blood-sucking insect, suggestions 

 which were brilliantly proved, from 1897 to 1899, by INIajor Ross, an 

 English army surgeon in the India service, and by Prof. Grassi, in 

 1899, who showed that mosquitoes belonging to the genera culex 



