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. The parasite was 

 formerly known as the h&matozoon or plasmodium malaria, although 

 the use of the latter term is incorrect ; the term hcemamceba is, however, 

 now generally employed. The parasite was first observed by Laveran 

 in 1880, and his discovery received confirmation from the independent 

 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 induction he arrived at the belief that the cycle of existence out- 

 side 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 ulti- 

 mately 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 corresponding 

 results in the case of the proteosoma infection of birds, where the para- 

 site is closely related to that of malaria. In birds affected with this 

 organism, he was able to trace all stages of its development, from the 

 time it entered the stomach along with the blood, till the time when it 

 settled in a special form in the salivary glands of the insect. Ross's 

 results were published in 1898. Exactly corresponding stages were 

 afterwards found in the case of the different species of the human para- 

 site, by Grassi, Bignami, and Bastianelli ; and these and other Italian 

 observers also supplied important information regarding the transmission 



