PROOF OF THE MOSQUITO DOCTRLNE 47 



London where endemic malaria does not exist, provided 

 that he was bitten by infected mosquitos. Ross had 

 now therefore worked out the whole story. The mos- 

 quito was the carrier of malaria from man to man. 

 INlalaria had no connection with miasms. The reason 

 why malaria was associated with marshes and water 

 was simply that mosquitos bred there. 



With these facts proved, it was clear that in order 

 to prevent malaria, it was necessary to protect man 

 from the infected mosquito and also to wage war 

 against it. Now this latter would have been a stupen- 

 dous task if it meant that war was to be wasfed against 

 all mosquitos. Here, however, direct scientific observ^a- 

 tion proved to Ross that the only species of mosquito 

 which could become infected belonged to a single group, 

 the Anophelinai. So that the question of extermina- 

 tion only affected that group. In consequence a 

 whole army of reseachers were set to work and it 

 was soon demonstrated that the anophelines preferred to 

 breed in small collections of water — those with a natural 

 earth bottom, such as small pools and patches of water 

 of all descriptions, margins of streams and lakes, and 

 odd receptacles coated with humus ; therefore the 

 problem of extermination was reduced in magnitude. 



The workers in the field of malarial research soon 

 brought to light another very important fact, i.e. 

 that, as demonstrated by Christophers and Stephens 

 and Koch, a very large number of people, including 

 children, harboured the parasite of malaria in their 

 blood without showing obvious symptoms of malaria. 

 In other words, that these people acted as the reservoirs 



