874 JOURNAL, BOMB AY NATURAL HISTORY SOCIETY, Vol. XV III. 



life of the parasite outside the body of man. But it was still an open 

 question in what situation further development took place. The fact 

 that conjugation occurred after the blood was drawn from the sick 

 suggested the idea that the parasite might find an alternate host in 

 the body of some blood-sucking insect. The observation that the 

 disease was most frequently found in marshy places and in latitudes 

 where mosquitoes were prevalent pointed to this insect as the most 

 probable host of the parasite. While this was a theory accepted by 

 many, even before Boss' brilliant and painstaking work converted 

 the theory into a fact, few have yet fully appreciated the significance 

 of his work. The fact cannot be too clearly impressed upon you that 

 it is not every mosquito which is capable of spreading the disease. 

 Had this been the case, Ross' task would have been a comparatively 

 easy one, but he had to find the mosquito which alone among 

 hundreds of others was capable of harbouring the parasite. Hundreds 

 upon hundreds of mosquitoes were carefully examined by him 

 without success, till one lucky day he observed a new kind of mos- 

 quito with " dappled ' wings. Success attended this discovery, 

 for in this mosquito with spotted wings the human malaria 

 parasite developed. I well remember, as I was coming out to 

 India for the first time, reading on board ship with great fasci- 

 nation Ross' new discovery. I then realised the importance of 

 knowing something about mosquitoes, but you will be surprised 

 to learn that some years elapsed before I was able to acquire 

 even the most elementary knowledge of these insects despite the faci 

 that I made every effort to obtain literature on the subject. Indeed, 

 at that time, so little was known about mosquitoes, that one had to 

 learn about these insects by studying them for oneself. While I was 

 stationed on military duty at Ellichpur a splendid opportunity pre- 

 sented itself for working at mosquitoes, especially that family of them 

 which is associated with human malaria — I mean those mosquitoes 

 which are generally known as Anopheles. At Ellichpur, among a 

 number of other anopheles which I found there, I was able to re- 

 cognise five new species, one of these is the mosquito which is res- 

 ponsible for spreading the epidemic which at present afflicts thi 

 Port and about which I propose to tell you more to-day. But be- 

 fore I can pass on to this part of the subject, I must detain you for 

 a minute while I describe, as briefly as I can, the various stages 



