244 MOSQUITOES OF NORTH AMERICA 
50 per cent of the persons bitten by infected mosquitoes (that had been kept 
twelve days or more after biting yellow-fever patients) were taken with the 
disease, and the yellow-fever diagnosis was confirmed by resident physicians in 
Havana who were above all others familiar with the disease in every form. 
Persons bitten by mosquitoes which had bitten a yellow-fever patient within 
less than twelve days did not contract the disease. In another series of experi- 
ments, seven persons were bitten by infected mosquitoes by placing the hand in 
a jar containing the insects, and five of them, or 71 per cent, contracted the 
disease. 
It was also found that yellow fever was produced by the injection of blood 
from the general circulation of a patient. Subcutaneous injections of two cubic 
centimeters of blood were followed by the disease, and the definite conclusion 
was reached that the parasite of yellow fever must be present in the general cir- 
culation, at least during the early stages of the disease, and that yellow fever 
may be produced, like malarial fever, either by the bite of the mosquito or by the 
injection of the blood taken from the general circulation. From these results 
this important corollary was reached, to quote Dr. Reed’s own words: “ The 
spread of yellow fever can be most effectually controlled by measures directed 
to the destruction of the mosquitoes and the protection of the sick against the 
bites of these insects.” 
One must be struck with the modesty of the men composing the Commission 
when, without a single symptom of self-laudation, the results of this remarkable 
experimental work, destined to revolutionize former ideas, were published under 
the simple title, “ The Etiology of Yellow Fever; An Additional Note.” Re- 
ferring again to the experimental patients it must be conceded that the heroism 
exhibited by these persons is beyond praise. Speaking of John R. Kissinger, a 
young Ohio soldier who was the first person bitten by infected mosquitoes, Dr. 
Reed says: 
“T can not let this opportunity pass without expressing my admiration of the 
conduct of this young Ohio soldier who volunteered for this experiment as he 
expressed it ‘solely in the interest of humanity and the cause of science, and 
with the only proviso that he should receive no pecuniary reward. In my 
opinion, this exhibition of moral courage has never been surpassed in the annals 
of the Army of the United States.” 
The next three cases were Spaniards, and all of these first four contracted the 
fever. After that, no more Spanish subjects could be secured. They had 
allowed themselves to be bitten largely through incredulity and for a money 
reward. After the fever appeared they lost their interest in the cause of science 
and preferred safety to money. Other Americans, however, immediately volun- 
teered, and, while praising their courage in the highest degree, we must not fail 
to point out here that the inspiration was derived from Dr. Reed himself. Noth- 
ing but the most absolute confidence in this remarkable man could have gained 
his subjects; and the confidence was justified, since this series of experiments, 
the results of which has already been of inestimable value to humanity, was 
completed without the loss of a single life as the direct result of the strictly ex- 
