26 SANITARY ENTOMOLOGY 



II. WHERE SHOULD THE INVESTIGATIONS OF INSECT TRANSMISSION 



BEGIN ? 



There are two distinct lines of approach to this problem of insect 

 transmission. The first is to work from the known disease and to ascer- 

 tain by experimentation what species of insects might be concerned in 

 its transmission. The other line of approach is to make a study of all 

 the insects which might be involved in disease transmission and to obtain, 

 by cultures and microscopic studies, a knowledge of the parasitic organ- 

 isms normally and occasionally found in these insects. Working on this 

 line of investigation, one might in time of an epidemic start with insects 

 visiting excreta and attempt to ascertain whether the organism of the 

 disease at that time epidemic occurs in any of these insects. 



The first line of investigations would arise from public necessity and 

 probably be initiated by physicians and parasitologists, or by the sugges- 

 tion of entomologists. 



The second line of investigations would probabl}^ originate as problems 

 assigned by a professor or head of a laboratory to students or investiga- 

 tors under his direction. It is highly desirable that such studies be com- 

 menced in as many institutions as practicable in the near future. Such 

 investigations will include bacteriological studies, protozoological studies, 

 and helminthological studies, as well as investigations of the life histories 

 of the insects, and the possible connection between them and disease 

 transmission. 



III. PLAN OF OPERATION 



Before starting out on any line of experiment in this subject, there 

 should be written down in concise form the facts already gleaned, on the 

 practical problems and the theories Avhich have occurred to the various 

 members of the group. A clearly outlined course of action should be 

 made and be carefully discussed and then the various steps in the inves- 

 tigations thus outlined should be read and modified to meet the changing 

 views resulting from the experiments. The course of the work should 

 always be kept plainly in view. Eacli step should be rigorously and 

 skeptically scrutinized for defects. 



Inasmuch as the investigation from this point will consist of the 

 answering by observation and experiment of a series of pointed ques- 

 tions, I shall proceed with my discussion in the form of queries. Prob- 

 ably many other vital queries will occur to the reader, but it is more 

 than possible that he may overlook some of these if not set forth here. 

 When each query is satisfactorily answered the problem is practically 

 solved. 



