16 THE YELLOW-FEVER MOSQUITO. 
It was also found that yellow fever was produced by the ‘jane 
of blood from the general circulation of a patient. Subcutaneot 
injections of 2 Gabi: centimeters of blood were followed by the dis- 
ease, and the definite conclusions were reached that the parasite of 
yellow fever must be present in the general circulation, at least dur- 
ing the early stages of the disease, and that yellow fever may be 
produced, like malarial fevers, either by the bite of the mosquito or 
by the injection of blood taken from the general circulation. From 
these results the 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. 
The organism that causes the disease has never been discovered. It 
is doubtless a protozoan, too small to be seen with the microscope, 
whose life cycle is partly in man and partly in the mosquito. 
SUBSEQUENT DEMONSTRATION. 
The finality of the work of the American Army commission was 
almost immediately accepted by sanitarians throughout the Tropics. 
Measures were at once instituted in the city of Habana, then under 
American control, looking to the eradication of yellow fever through 
antimosquito measures. The enormous success of this work, car- 
ried on under the direction of Maj. (now Col.) Gorgas, is a matter 
of history, and by the use of similar methods the same efficient sani- 
tarian has since that time wiped out yellow fever in the Isthmian 
Canal Zone. Similar work has been done by the sanitary officials in 
Brazil and in Mexico and other countries. 
A striking instance of the value of this discovery was shown dur- 
ing the yellow fever outbreak in New Orleans in 1905. Down to the 
middle of June of the summer of 1905 this outbreak threatened te 
parallel the disastrous outbreak of 1878, and even to exceed that dis- 
aster in severity. Antimosquito measures were undertaken, however, 
and pushed with great energy and with much expenditure of funds, 
the result being a perfectly obvious saving of from 3,000 to 4,000 lives 
during that summer which would undoubtedly have been lost six 
vears earlier. 
REMEDIES. 
The general question of remedies for mosquitoes is considered in 
Warmers’ Bulletin 444, and it will therefore be unnecessary to enter 
upon this subject in this bulletin. Readers are also referred to Farm- 
ers’ Bulletin 450, on malaria, as related to this general subject. 
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