582 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1021. 



while scientifically sound, does not especially appeal to the writer 

 from the practical point of view. The case is altogether too obvious. 



It is so obvious, in fact, as amply to justify the general crusade 

 against the house fly that began in this country about 1908 or 1909. 

 Boards of health, both State and local, women's clubs, civic bodies, 

 including the American Civic Association, and very many news- 

 papers have pushed the campaign against the house fly with great 

 vigor. The destruction of the house fly has been taught in the 

 schools and prizes have been awarded to the child killing the greatest 

 number of flies. It should be noted that a few members of the So- 

 ciety for the Prevention of Cruelty to Animals have objected to such 

 teachings ; but then there are people who are opposed to vaccination 

 against smallpox and still others who object to well-planned vivisec- 

 tion. While this tremendous crusade is doing a great deal of good 

 educationally, a lot of energy is being misdirected in a way. Crush- 

 ing a few hundred or a few thousand or a few hundreds of thousands 

 of flies with a paddle will do little good if their breeding places are 

 left undisturbed. 



We have now described briefly many of the principal discoveries 

 of the relation of certain insects to certain diseases. Very many 

 more discoveries have been made and doubtless very many more are 

 yet to be made, and many trained workers are investigating many 

 sanitary problems with the idea of possible insect carriage constantly 

 in mind. Some poor guesses have been made on insufficient grounds, 

 which have been widely heralded before thorough laboratory investi- 

 gation and transmission experiments, but all plausible guesses must 

 be carefully considered, and the men trained in investigation work of 

 this kind are rapidly increasing in number. Already Pierce has 

 tabulated in his recent work on Sanitary Entomology more than 

 two hundred diseases that have been shown to be carried by insects, 

 and the bibliographical journals and reviews devoted to such subjects 

 announce new discoveries almost every month. 



Most of the important discoveries have been made by pathologists, 

 bacteriologists, and protozoologists, or by a class of workers calling 

 themselves by the general term " parasitologists." But transmis- 

 sion of a disease by an insect or a group of insects once established, 

 the trained entomologist comes in, gives his knowledge of the insect 

 vector, and investigates every phase of its biology and behavior. An 

 admirable estimate of what medical entomology to-day means or 

 should mean is given by Colonel Alcock, Assistant Director of the 

 Tropical Diseases Bureau, of London, himself an investigator of note, 

 in the following words : 



Medical entomology, too, during the last decade has become more critical and 

 more formal. We are not now suddenly afraid of an insect merely because it 

 has been caught in the act of sucking blood; nor even when dealing with an 



