WHOLE VOL. APPLIED ENTOMOLOGY HOWARD 1 33 



transmission of disease was brought before the people with immense 

 force by Ross' work. Malaria was practically a world-wide malady ; 

 millions of people were subject to it ; and it is therefore no wonder 

 that the attention of investigators everywhere was drawn to this 

 new field and that by their work the field was broadened out to an 

 extraordinary degree. Almost immediately Ross' results were con- 

 firmed in Italy, and antimalaria work from the mosquito standpoint 

 was begun in many parts of the world. 



In a very short time the work of Reed, Carroll, and Lazear demon- 

 strated that without a doubt yellow fever is also mosquito-borne and 

 is transferred only by a certain si>ecies of mosquito. Medical ento- 

 mology became at once an important field of investigation. Dis- 

 coveries followed one another with rapidity. New schools of tropical 

 medicine were founded, and teaching in these subjects was begun in 

 the medical colleges. In the thirty years that have elapsed since Ross' 

 discovery thousands of papers have been published giving the results 

 of research work all over the world, and large and comprehensive 

 books have been published on medical entomology. In fact, the world's 

 output of scientific papers relating to this kind of scientific work has 

 become so great that their titles alone crowd the pages of the biblio- 

 graphical journals, while at least one journal of this kind has been 

 established solely for the review of this mass of special scientific 

 literature. 



So rapidly did discoveries mount in number that as early as 1921 

 W. D. Pierce, in the large book edited by him and entitled " Sani- 

 tary Entomology," devoted 27 pages to the mere listing (in fine 

 print) of the maladies of man and domestic animals that are spread 

 by insects, of their insect transmitters, and of the secondary hosts of 

 these insects where such are involved. The four years and more of 

 the world war, while interrupting scientific investigation to a cer- 

 tain extent, incited work on some of the problems of this nature, and 

 many important facts were discovered and many important results 

 were gained. 



It is perfectly true that most of the main discoveries in medical 

 entomology have been made by medical men, but all future work 

 demands the intimate cooperation of pathologists and entomologists. 

 The control of an insect-borne disease, whether of man or of domes- 

 tic animals, means primarily the control of the carrier; and who so 

 competent to investigate the possibilities in that direction as the man 

 trained in economic entomology? Down to the present time perhaps 

 the entomologists have realized this more than the medical men have 

 done. It has happened too often that medical investigators have 



