250 MOSQUITOES OF NORTH AMERICA 
slight epidemic of this affection among the soldiers in garrison in the island of 
Salut in French Guiana. In a space of eight or ten days a third of the effective 
force of this little garrison was attacked by the fever, which caused no deaths 
and disappeared as suddenly as it came. The writers were struck with the 
analogy existing between that outbreak and the case of yellow fever which they 
had produced by an hereditarily infected mosquito. This inflammatory fever 
is unknown except in countries in which yellow fever is endemic. Its epidemic 
appearances have been often preceded or followed by certain and severe cases of 
yellow fever. They think that if it shall be shown by future experiments that the 
yellow-fever mosquito hereditarily infected is capable only of producing light 
cases, it will be important to consider whether the so-called inflammatory fever 
does not differ from yellow fever simply by this mode of infection. 
The final conclusions of the French commisssion are published in their second 
and third Memoirs, issued by the Pasteur Institute of Paris in January and 
February, 1906. The conclusions of the second Memoir include the observations 
just recorded, but the conclusions as a whole are so important that they may be 
stated in detail : 
“(1) The transmission of the virus of yellow fever is possible hereditarily in 
Stegomyia fasciata. In the case, unique up to the present, in which this has been 
observed, the eggs which gave birth to the hereditarily infected individuals of the 
first generation had been laid by a mosquito which had been infected a suffi- 
ciently long time previously from a yellow-fever patient. 
“(2) The infection of Stegomyia fasciata hereditarily does not appear to play 
a considerable part in the propagation of yellow fever. It is capable, neverthe- 
less, of causing a recurrence of a recently stamped out epidemic, and it is there- 
fore very important to take it into consideration in prophylactic organization. 
“(3) Itis possible that the passage of the yellow-fever virus from one genera- 
tion of the mosquito to another, through the egg, causes the attenuation of the 
virus. 
(4) The mosquito does not become infected by absorbing either the blood 
coming from the hemorrhages common to patients in the second stage of yellow 
fever or from the black vomit or from the dejections of the patients. The mos- 
quito, even in captivity, absorbs these substances only when it is compelled by 
hunger. 
“(5) The larve of Stegomyia fasciata reared in water containing fresh bodies 
of infected mosquitoes do not contract the infection and the adults which issue 
from them are not virulent. 
“(6) The infected mosquito kept at a temperature near 20° C. does not 
appear to possess the infecting power. 
(7) We have not succeeded in infecting mosquitoes from subjects during 
the period of incubation of yellow fever. 
“(8) The virus of yellow fever can be artificially transmitted from mosquito 
to mosquito. We have not succeeded in causing several successive passages of 
this kind. 
“ (9) This mode of transmission is possible only under laboratory conditions. 
Tt does not exist in nature. Healthy adult mosquitoes kept in contact with the 
bodies of infected mosquitoes do not contract the infection and are incapable 
of transmitting yellow fever. 
