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 role 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 r 61 e 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 spiders 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 
