variety. I wish 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 locality, 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 malaria-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.
(b) What are the habits of the dangerous varieties.
I hope, therefore, that I may be permitted to urge the desirability 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 unequivocal 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 entered upon in Germany, Italy, America, and Africa will assist any which may be undertaken in India, though there is reason for thinking that the malaria-bearing species differ in various countries.
As each species is detected it will be possible to attempt measures at once for its extermination in given localities as an experiment.
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 importance.