8 INTRODUCTION 



man has never been practically demonstrated, though 

 there is strong presumptive evidence in its favour. 



Then followed the well-known discovery by 

 Ronald Ross, published by him in 1897-9 : first, that 

 the domestic grey gnat conveys the malaria parasite 

 of birds (Proteosoma danilewski of Labbe) from one 

 bird to another, and secondly, that the human 

 malaria parasite of Laveran is similarly transmitted 

 by certain mosquitos of the dapple-wing type that 

 belong to the sub-family called Anopheline. 



As in the case of filariasis, the possibility of the 

 transmission of malaria by mosquitos had been 

 suggested by many observers ; but this discovery 

 differed from that of Hanson's, inasmuch as the 

 whole of the life-history of the malaria parasite in the 

 mosquito was clearly demonstrated and proved by 

 actual experiment. Its confirmation was soon forth- 

 coming from Koch, Daniels, and from Bignami, 

 Bastianelli, Stephens, Christophers, and many others. 

 Practical transmission experiments in human beings 

 were performed by many observers, and this discovery 

 is now absolutely proved. 



Serious attention was consequently drawn to mos- 

 quitos as dangerous pests. Immediately following 

 his discovery, Ross, in 1899, suggested to the Indian 

 Government the possibility of reducing mosquitos in 

 a malarious district, basing his proposals on observa- 

 tions and experiments conducted during the previous 

 years in India. These experiments showed that 

 mosquitos in a house could be reduced by the simple 

 procedure of periodically emptying out the rain-water 



