Early Suggestions / 3 



thinking that the source of the virus was decomposing matter which 

 the mosquito took up and accidentally inoculated into man. Beau- 

 perthuy not only discussed the r61e of mosquitoes in the transmission 

 of disease, but he taught, less clearly, that house-flies scatter patho- 

 genic organisms. It seems that Boyce (1909) who quotes extensively 

 from this pioneer work, does not go too far when he says "It is Dr. 

 Beauperthuy whom we must regard as the father of the doctrine of 

 insect-borne disease." 



In this connection, mention must be made of the scholarly article 

 by the American physician, A. F. A. King who, in 1883, brought 

 together an all but conclusive mass of argument in support of his 

 belief that malaria was caused by mosquitoes. At about the same 

 time, Finley, of Havana, was forcefully presenting his view that the 

 mosquito played the chief r61e in the spread of yellow fever. 



To enter more fully into the general historical discussion is beyond 

 the scope of this book. We shall have occasion to make more 

 explicit references in considering various insect-borne diseases. 

 Enough has been said here to emphasize that the recognition of 

 insects as factors in the spread of disease was long presaged, and that 

 there were not wanting keen thinkers who, with a background of 

 present-day conceptions of the nature of disease, might have been in 

 the front rank of investigators along these lines. 



THE WAYS IN WHICH ARTHROPODS MAY AFFECT THE HEALTH 



OF MAN 



When we consider the ways in which insects and their allies may 

 affect the health of man, we find that we may treat them under three 

 main groups: 



A. They may be directly poisonous. Such, for example, are the 

 scorpions, certain ■■«piders and mites, some of the predaceous bugs, 

 and stinging insects. Even such forms as the mosquito deserve 

 some consideration from this viewpoint. 



B. They may be parasitic, living more or less permanently on 

 or in the body and deriving their sustenance from it. 



Of the parasitic arthropods we may distinguish, first, the true 

 parasites, those which have adopted and become confirmed in the 

 parasitic habit. Such are the itch mites, the lice, fleas, and the 

 majority of the forms to be considered as parasitic. 



In addition to these, we may distinguish a group of accidental, or 

 facultative parasites, species which are normally free-living, feeding on 



