401 



fomites of the worst kind, collected from fatal cases of yellpw fever, and the 

 result has always been completely negative. 



After these experimental proofs and the collateral evidence that I 

 have recalled, there can be no excuse for considering fomites as a factor 

 in the propagation of yellow fever. 



In order to demonstrate my second proposition, that the mosquito 

 appeal's to be the only insect capable of transmitting the yellow fever 

 infection, I must first recall the manner in which the yellow fever mosquito 

 was discovered by me in 1880. This happened about the time when Bemiss, 

 Stone and other American yellow-fever experts had invented the "nidus 

 theory" in order to account for the fact that the propagation of the disease, 

 in places where the disease is transmissible, is not effected through direct 

 contact with yellow fever patients or their secretions, nor by inhaling the 

 emanations from their bodies, nor by using contaminated food or beverages. 

 I had however conceived a different solution of the problem. My own 

 conclusion had been that the germ of yellow fever must be one which is 

 pathogenous for human beings only when it is introduced by inoculation, 

 and that the natural transmitter of the disease must be a blood-sucking 

 insect, peculiar to the yellow fever zone and whose existence and functional 

 activity should be incompatible with certain degrees of cold and with 

 certain altitudinal limits as well as with other conditions which are known 

 to control the spread of the disease. By searching for such all insect in 

 Havana, I came across the Culex mosquito, Desv. (Stegomyia fasciata, 

 Theo.) in which I had observed certain peculiarities in the manner of 

 laying its ova and in its readiness to renew its bites whenever the digestion 

 of a previous meal had been completed, both of which peculiarities seemed 

 to differentiate it from the generality of gnats. Upon investigation, that 

 particular mosquito was found to fulfill all the conditions which I had 

 postulated in my theory, in a manner which was considered remarkable 

 by several European experts when I published in the Archives de Médecine 

 X avale (Avril 1883, p. 308), the following table in which the climateric 

 conditions of yellow fever were confronted with the vital conditions of the 

 C. mosquito (Stegomyia). 



