APPENDIX C. 



MALARIAL FEVER. 



IT has now been conclusively proved that the cause of malarial 

 fever is a protozoon of which there are several species. They 

 belong to the hsemosporidia (a sub-class of the sporozoa) which 

 are blood parasites, infecting the red corpuscles of mammals, 

 reptiles, and birds. The parasite was formerly known as the 

 hcematozoon or plasmodium malarice, although the use of the 

 latter term is incorrect ; the term hcemamoeba is, however, now 

 generally employed. The parasite was first observed by Laveran 

 in 1880, and his discovery received confirmation from the in- 

 dependent researches of Marchiafava and Celli, and later from 

 the researches of many others in various parts of the world. 

 Golgi supplied valuable additional information, especially in 

 relation to the sporulation of the organism and the varieties in 

 different types of malarial fever. In this country valuable work 

 on the subject was done by Manson, and to him specially belongs 

 the credit of regarding the exflagellation of the organism as 

 a preparation for an extra-corporeal phase of existence. By in- 

 duction he arrived at the belief that the cycle of existence outside 

 the human body probably took place in the mosquito. It was 

 specially in order to discover, if possible, the parasite in the 

 mosquito, that Ross commenced his long series of observations, 

 which were ultimately crowned with success. After patient and 

 persistent search, he found rounded pigmented bodies in the 

 wall of the stomach of a dapple-winged mosquito (a species of 

 Anopheles) which had been fed on the blood of a malarial 

 patient. The pigment in .these bodies was exactly similar to 

 that in the malarial parasite, and he excluded the possibility of 

 their representing anything else than a stage in the life cycle of 

 the organism. He confirmed this discovery and obtained cor- 

 responding results in the case of the proteosoma infection of 

 birds, where the parasite is closely related to that of malaria. 



521 



