ROSSES DISCOVERY 41 



infected the mosquito ; and then when the infected 

 mosquito, which liad now become the carrier, bit 

 man, it infected him. 



As the history of tliis epoch-making discovery is 

 of great scientific and practical interest, I cannot do 

 better than give it in Professor Ross's own words. 



Professor Ross had returned to his regimental 

 duties in India ; before setting out, however, he had 

 a conversation with Dr. Manson (now Sir Patrick 

 Manson) on the best method of experiment to test 

 whether, as in the case of the Filaria Bancrofti dis- 

 covered in the mosquito by INIanson, a mosquito might 

 likewise act as host to the malarial parasite. Ross says : 



" We agreed tliat the proper course would be to 

 select patients wliose blood was rich in gametocytes 

 (the name now given to those forms of the parasite 

 of whicli some produce motile filaments), and to 

 attempt to trace in the tissues of these insects the 

 development of the said motile filaments which we 

 thouglit were flagellate spores. In fact it was pro- 

 posed that I should adopt exactly the procedure 

 employed by JManson in regard to Filciria Bancrofti.'' 



After innumerable failures to find anything definite 

 in the bodies of the mosquitos which he examined for 

 the purpose of trying to trace out the further life 

 history of Laveran's parasites in the mosquito, Ross, 

 being now at Secunderabad (1907), says: 



" I commenced work by making a careful survey 

 of the various kinds of mosquitos which were to be 

 found in the officers' quarters, 'm the regimentgj 



