August 8, 1919] 



SCIENCE 



125 



phrase, has never been more terrible exempli- 

 fied than by Germany, yesterday wielding her 

 vast might of intellect and muscle to domi- 

 nate the world; to-day cast down to the very 

 dust and utterly impotent. 



IsTature herself, working through the process 

 we have named evolution, has produced an 

 agency, the human reason and intelligence, 

 one of the main purposes of which is to find 

 a better way, i. e., a more efficacious, more 

 certain, and less destructive way than war for 

 solving problems of human preservation and 

 realization. 



Wm. E. Ritter 



La Jolla, Calif., 



SOME NECESSARY STEPS IN ANY 

 ATTEMPT TO PROVE INSECT 

 TRANSMISSION OR CAUSA- 

 TION OF DISEASE 



The study of the causation of disease is at- 

 tracting far more attention to-day than it 

 ever has in the past, but it is to be regretted 

 that there is not a larger proportion of this 

 effort being directed toward locating the pos- 

 sible intermediate hosts and invertebrate 

 carriers. 



Many excellent investigations have been 

 carried out with all other phases complete, but 

 the question of invertebrate carriers is often 

 left in a very indeterminate stage. The ma- 

 jority of the investigations which have been 

 seriously undertaken to determine inverte- 

 brate carriers have been conducted on other 

 continents than ours. There is a great field 

 for investigation along these lines open to in- 

 vestigators in America. In order to stimu- 

 late such research, I have attempted in this 

 paper to set down some of the necessary steps 

 for successful investigation. 



I. COOPERATION 



I consider essential to a thorough investiga- 

 tion of disease transmission, the establishment 

 of a perfect working agreement and hearty 

 cooperation between one or more physicians 

 and diagnosticians, one or more parasitol- 

 ogists, and one or more entomologists. It is 

 not safe nor does the effort bring the proper 



amount of credence, when one man attempts 

 to do the whole work. Each phase of such an 

 investigation should be handled by an expert 

 on that phase. The day of the solitary in- 

 vestigator is past and we are now in an era of 

 group-investigations which carry with them 

 weight and conviction. Of course certain pre- 

 liminary steps may easily be taken by any one 

 member of a proposed group or it may be 

 possible that they may arrive at an advanced 

 stage by independent work, but the time will 

 come in each investigation when a coopera- 

 tion of investigators will attain the most 

 satisfactory results. 



n. 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 

 ascertain by experimentation what species of 

 insects might be concerned in its transmis- 

 sion. The other line of approach is to make 

 a study of all the insects whch might be in- 

 volved in disease transmission and to obtain, 

 by cultures and microscopic studies, a knowl- 

 edge of the parasitic organisms normally and 

 occasionally found in these insects. Working 

 on this line of investigation, one might in time 

 of an epidemic start with insects visiting ex- 

 creta 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 rise 

 from public necessity and probably be in- 

 itiated by physicans and parasitologists, or by 

 the suggestion of entomologists. 



The second line of investigations would 

 probably originate as pro Jems assigned by a 

 professor or head of a laboratory to students 

 or investigators 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 iwssible connection between 

 them and disease transmission. 



