Mosquitoes and Yellow Fever 
205 
volunteers presenting themselves, one of these mosquitoes died the 
sixty-ninth and one the seventy-first day after their original con¬ 
tamination, without it being determined whether they were still 
capable of transmitting the disease. 
So carefully carried out was this work and so conclusive were the 
results that Dr. Reed w^as justified in writing: 
“Six months ago, when we landed on this island, absolutely noth¬ 
ing was known concerning the propagation and spread of yellow 
fever—it was all an unfathomable mystery—but today the curtain 
has been drawn—its mode of propagation is established and we know 
that a case minus mosquitoes is no more dangerous than one of 
chills and fever.’’ 
The conclusions of the Commission were fully substantiated by 
numerous workers, notably Dr. Guiteras of the Havana Board of 
Health, who had taken a lively interest in the work and whose 
results were made known in 1901, and by the Brazilian and French 
Commission at Sao Paulo, Brazil, in 1903. 
Throughout the work of the Army Commission and down to the 
present time many fruitless efforts have been made to discover the 
specific organism of yellow fever. It was clearly established that 
the claims of Sanarelli for Bacillus icteroides were without founda¬ 
tion. It was found, too, that whatever the infective agent might 
be it was capable of passing through a Berkefeld filter and thus be¬ 
longs to the puzzling group of “filterable viruses.” It was further 
found that the virus was destroyed by heating up to 55° C for ten 
minutes. It is generally believed that the organism is a Protozoan. 
The question of the hereditary transmission of the yellow fever 
organism within the mosquito w r as left unsettled by the Army Com¬ 
mission, though, as w r e have seen, it was raised by Finlay. Marchoux 
and Simond, of the French Commission devoted much attention to 
this phase of the problem and basing their conclusions on one ap¬ 
parently positive case, they decided that the disease could be trans¬ 
mitted through the egg of an infected Aedes calopus to the second 
generation and thence to man. The conclusion, w r hich is of very 
great importance in the control of yellow fever, has not been verified 
by other workers. 
Once clearly established that yellow fever w T as transmitted solely 
by mosquitoes, the question of the characteristics, habits, and geo¬ 
graphical distribution of the insect parrier became of vital import¬ 
ance. 
