8 PHILOSOPHICAL SOCIETY OF WASHINGTON. 
differences between the whites and blacks—such as even cerebral 
capacity and variations in the skeleton—might be susceptible of 
explanation by blood changes resulting from malaria. The marrow 
of bones was also a pigment-forming tissue, and the aching of bones 
during ague, especially in so-called “ break-bone” fever, suggested 
congestion and modified nutrition in the osseous structures, such as 
might eventually lead to modification in the skeleton. The inhabi- 
tants of oriental countries especially were more vigorous and intel- 
ligent if they lived in elevated regions, than were others inhabiting 
mosquito-infected lowlands and sea coasts. 
In further support of the mosquital origin of malarial fevers 
numerous noted medical authorities were cited, showing that, in 
all parts of the world where these diseases prevail, immunity was 
secured by protecting the body from mosquito bites. The geo- 
graphical distribution and seasonal evolution of mosquitoes and 
other proboscidian insects were shown partially to agree with the 
times and places in which malarial diseases prevail; though from 
lack of information conclusive evidence on this point was yet 
wanting. There was, however, a general admission on the part of 
medical authorities that swarms of these insects in almost any 
locality were a pretty sure sign of malignancy. 
On the other hand numerous instances were adduced from “ Nar- 
ratives”’ and “ Travels” in which the bodies of persons had been 
covered with pustules, “ resembling small-pox,” from mosquito bites 
without any subsequent occurrence of fever having been recorded 
by the narrating authors. 
This opposing evidence was inconclusive, (1) because the authors 
cited were not in search of medical information; (2) because the 
period of incubation, being often long and uncertain, fever may 
have occurred after the mosquito bites had been forgotten; (3) 
the insect proboscis (like a vaccine lancet unarmed with virus) 
might be uncontaminated with fever poison, or fever germs; and 
(A) successful inoculations of specific germ poisons are not usually 
followed by immediate local suppuration at the point of puncture, 
but only after a certain period of incubation, the immediate local 
inflammation being rather preventive of subsequent blood infection. 
The possible spread of yellow-fever contagion by the inoculating 
proboscis of the mosquito carrying infecting matter drawn from 
the blood of yellow-fever patients to unaffected persons was sug- 
gested. In epidemics, the spread of the disease stopped as soon as 
a freezing temperature paralyzed the mosquito, &c. 
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