PROCEEDINGS OF THE 



ENTOMOLOGICAL SOCIETY OF WASHINGTON 



VOL. 20 MAY, 1918 No. 5 



THREE HUNDRED AND THIRTEENTH MEETING, MAY 2, 1918 



MEDICAL ENTOMOLOGY A VITAL FACTOR IN THE PROSECU- 

 TION OF THE WAR. 



BY W. DWIGHT PIERCE. , 



The Biological Complex. 



The farther one progresses in the study of biology the more he 

 becomes impressed with the absolute interdependence of all forms 

 of organic life. It is impossible to conduct a study of man or any 

 species of animal without soon reaching some phase of the question 

 which demands attention to some other species, until finally a 

 complete biological study has led one far afield. For instance, the 

 investigator, working upon a given disease, finds that the disease 

 is caused by some organism. He proceeds to study the organism 

 and soon finds that it must have a phase of its life outside the host 

 as well as in the host. In his further investigation of the life cycle 

 of the parasite he often finds that there is another host concerned. 

 Thus, before he has gone very far in his investigation he has three 

 widely separate species of life intimately joined together in a 

 biological complex. It is interesting to note that the intermediate 

 or primary hosts of parasites are often found among the inverte- 

 brates, especially the insects. 



In tracing farther the study of such a parasite the investigator 

 is led to inquire into the life history of the insect and may find that 

 this insect attacks other vertebrate hosts. The question then is to 

 determine whether the parasite of the insect is also found in the 

 newly discovered vertebrate host, and it may often be learned that 

 some wild animal is the reservoir of a disease of man or domestic 

 animals, and thus the complex becomes greater and greater the 

 farther, one investigates. It is therefore obvious that a perfect 

 sanitation and prevention of disease necessitates a complete knowl- 

 edge of all forms of life and their interrelationships. 



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