46 POPULAR SCIENCE MONTHLY. 



variety. I wisli merely to indicate what, so far as I can see at 

 present, may become a very simple means of eradicating malaria. 



One thing may be said for certain. "Where previously we have 

 been unable to point out the exact origin of the malaria in a local- 

 ity, and have thought that it rises from the soil generally, we 

 now hope for much more precise knowledge regarding its source; 

 and it will be contrary to experience if human ingenuity does not 

 finally succeed in turning such information to practical account. 



More than this, if the distinguishing characteristics of the ma- 

 laria-bearing mosquitoes are sufficiently marked (if, for instance, 

 they all have spotted wings), people forced to live or travel in 

 malarious districts will ultimately come to recognize them and to 

 take precautions against being bitten by them. 



Before practical results can be reasonably looked for, however, 

 we must find precisely — 



(a) What species of Indian mosquitoes do and do not carry 

 human malaria. 



(h) What are the habits of the dangerous varieties. 



I hope, therefore, that I may be permitted to urge the desira- 

 bility of carrying out this research. It will no longer present any 

 scientific difficulties, as only the methods already successfully 

 adopted will be required. The results obtained will be quite un- 

 equivocal and definite. 



But the inquiry should be exhaustive. It will not suffice to 

 distinguish merely one or two malaria-bearing species of mosquito 

 in one or two localities; we should learn to know all of them in all 

 parts of the country. 



The investigation will be abbreviated if the dangerous species 

 be found to belong only to one class of mosquito, as I think is 

 likely; and the researches which are now being energetically en- 

 tered upon in Germany, Italy, America, and Africa will a'ssist any 

 which may be undertaken in India, though there is reason for 

 thinking that the malaria-bearing species differ in various coun- 

 tries- 



As each species is detected it will be possible to attempt meas- 

 ures at once for its extermination in given localities as an ex- 

 periment. 



I regret that, owing to my work connected with 'kala-azar, I 

 have not been able to advance this branch of knowledge as much 

 during my term of special duty as I had hoped to do; but I think 

 that the solution of the malaria problem which has been obtained 

 during this period will ultimately yield results of practical im- 

 portance. 



