Roberton. — Malaria and Mosquitos. 233 



corroborative experiments were made in different parts of the 

 world. In Italy work undertaken to show that the same was 

 true of human malaria was equally successful. 



Ross had early found that it was not every kind of mos- 

 quito in which the malarial parasite could continue its 

 development. It was now a practical question to decide 

 what mosquitos were and what were not responsible for 

 the conveyance of malarial infection. For this purpose a 

 proper classification of mosquitos was necessary, and, curiously 

 enough, the classification of these insects was found singularly 

 deficient and confusing. 



The term ''mosquito" is itself an indefinite one. It is 

 the diminutive of mosca, the Spanish word for fly. Ap- 

 plied by the Spaniards to certain troublesome insects, it was 

 adopted into other languages, and came in time to include 

 not only different species but also different genera. Most of 

 them belong to the gnat family, or Culecidce, and there is 

 indeed very little, if any, difference except in name between 

 many gnats found in temperate regions and mosquitos in 

 tropical countries. I am using the term " mosquito " to-night 

 in its widest sense. 



The deficiency in the classification of mosquitos was soon 

 overcome. The whole civilised world was more or less in- 

 terested, and numerous observers in each country helped in 

 the work. The British Museum authorities issued a pamphlet, 

 "How to collect Mosquitos," and sent it to British officials 

 throughout the world, both in British dominions and at 

 consular agencies elsewhere, at the same time asking that 

 specimens of species found might be forwarded to the 

 Museum. In this way a large mass of valuable material 

 was obtained, which aided materially in the classification and 

 identification of the species responsible for the carriage of 

 malaria. 



Many different species were used to repeat Ross's experi- 

 ment — i.e., that of raising mosquitos from larvae and letting 

 them feed on malarial blood to see whether the malarial 

 parasite would develope in their stomachs ; but the same con- 

 clusion was come to all over the world — that it was only 

 among the members of the genus Anopheles that this hap- 

 pened. Where human malaria existed Anopheles was always 

 found, and, roughly speaking, the distribution of Anopheles 

 over the globe corresponded with the distribution of malaria. 

 The knowledge of the actual mosquito concerned being once 

 attained, the experimental research in connection with the 

 prevention of malaria was much facilitated. 



There still remained many doubters of the truth of the 

 discovery. In some high places in India ridicule was cast 

 on the idea, and the ordinary lav mind was able to find manv 



