1912 ENTOMOLOGICAL SOCIETY. 49 



place inside, where the nucIeuB of the Zygote divides and a number of smaller 

 bc^dies are formed. From theise, still smaller bodies are formed which become 

 needle-shaped in character, until at length the whole cyst is filled with a mass of 

 needle-shaped bodies which are spores. The cyst then bursts and these spores are 

 liberated into the body cavity of the mosquito, which, of course, is a blood cavity. 

 The minute needle-shaped spores are carried on to the salivary gllands and bore 

 into the salivary ducts, with the result that, when the' mosquito bites another 

 person, large numbers of the small spores of the malarial organism are pumped, 

 together with the salivary fluid, into the puncture, and thus enter the blood system 

 of another person, who, in consequence, may develop the fever. The natives in 

 malarial countries are usually immune to the effects of the malarial organism, 

 and may be compared to the big game which are carriers of the organism of 

 ISTagana. It has been found that babies and infants act very largely as carriers 

 of the organism, and the percentage of children infected decreases as they grow 

 older, until after twelve years of age they may be rarely infected. Such infected 

 children, of course, will serve as reservoirs of the disease. 



With the discovery that the mosquito was the carrier of the causative organism 

 of the disease, the question of the prevention and eradication of malaria resolved 

 itself into the problem of the eradication of the mosquito, and this, in turn, pTac- 

 tically implied the destruction of the breeding-places of the mosquito. The mos- 

 quito, as is well-known, has an aquatic larval stage. The larvae living in the 

 water on microscopic organisms are compelled to come to the surface to breathe. 

 By covering the surface of the water with a thin film of oil, such as kerosene, 

 the breathing of the mosquito larvas is prevented, and consequently they are killed. 

 The chief meanis, therefore, which are generally adopted for destroying the mos- 

 quito are the draining of marshes and other places where water collects and serves 

 as breeding places, and also the treatment of permanent standing water with kero- 

 sene or crude oil. In addition, human habitations are screened to prevent the 

 entrance of the mature mosquitoes. Standing water around houses, however small 

 it may be in quantity, has to be treated, as the mosquitoes breed in most unlikely 

 places. The success wihich has followed the adoption of anti-mosquito measures 

 is remarkable. 



In Havana, which at one time was a "white man's grave," Yellow Fever, 

 which is carried by a species of Stegomyia, has been eradicated since the United 

 States authorities commenced in 1898 a campaign against the mosquito. The 

 United States Government is now able to construct the Panama Canal, owing to 

 the mosquito control measures which they have adopted, and the same tale of the 

 reduction in the number of cases of Malaria is told wherever preventive measures 

 have been adopted. 



To my mind, these facts indicate, among other things, how important a bearing 

 a very small entomological fact may have on the welfare of man. How little did he, 

 who first discovered the way in which the mosquito larva breathes, think that millions 

 of lives would be saved through taking advantage of the phenomenon he observed, 

 and this fact illustrates how great significance may be attached to an entomo- 

 logical observation, though it may have appeared small when it was made. The 

 investigations on Sleeping Sickness and Malaria have demonstrated most strongly 

 the necessity of complete studies with regard to the life-histories and bionomics 

 of insects, and have given a foremost place to entomological investigation among 

 those sciences upon which we shall have to depend for our future welfare. 



In conclusion, I would commend the following passage written by that foremost 

 EnglisHi scientist, Sir Eay Lankester: 



4 E.S. 



