YELLOW FEVER AND MOSQUITOES. 229 



insect, although the experiments of Finlay seemed to show that this in- 

 sect was not a mosquito of the genus Culcx, such as he had used in 

 his inoculation experiments. I also urged that efforts should be made to 

 ascertain definitely whether the disease can be communicated from man 

 to man by blood inoculations. Evidently if this is the case the blood 

 must contain the living infectious agent upon which the propagation of 

 the disease depends, notwithstanding the fact that all attempts to dem- 

 onstrate the presence of such a germ in the blood, by means of the micro- 

 scope and culture methods, had proved unavailing. I had previously 

 demonstrated by repeated experiments that inoculations of yellow fever 

 blood into lower animals — dogs, rabbits, guinea-pigs — give a negative 

 result, but this negative result might well be because these animals were 

 not susceptible to the disease and could not be accepted as showing that 

 the germ of yellow fever was not present in the blood. A single inocula- 

 tion experiment on man had been made in my presence in the city of 

 Vera Cruz, in 1887, by Dr. Daniel Euiz, who was in charge of the civil 

 hosi)ital in that city. But this experiment was inconclusive for the 

 reason that the patient from whom the blood was obtained was in the 

 eighth day of the disease, and it was quite possible that the specific germ 

 might have been present at an earlier period and that after a certain 

 number of days the natural resources of the body are sufficient to efEect 

 its destruction, or in some way to cause its disappearance from the cir- 

 culation. 



This was the status of the question of yellow fever etiology when Dr. 

 Eeed and his associates commenced their investigations in Cuba during 

 the summer of 1900. In a 'Preliminary Xote,' read at the meeting of 

 the American Public Healtli Association, October 22, 1900, the board 

 gave a report of three cases of yellow fever which they believed to be the 

 direct result of mosquito inoculations. Two of these were members of 

 the board, viz. : Dr. Jesse W. Lazear and Dr. James Carroll, who volun- 

 tarily submitted themselves to the experiment. Dr. Carroll suffered a 

 severe attack of the disease and recovered, but Dr. Lazear fell a victim 

 to his enthusiasm in the cause of science and humanity. His death oc- 

 curred on September 25th, after an illness of six days' duration. About 

 the same time nine other individuals who volunteered for the experiment 

 were bitten by infected mosquitoes — i. e., by mosquitoes which had pre- 

 viously been allowed to fill themselves with blood from yellow fever 

 cases — and in these cases the result was negative. In considering the 

 experimental evidence thus far obtained the attention of the members 

 of the board was attracted by the fact that in the nine inoculations with 

 a negative result "the time elapsing between the biting of the mosquito 

 and the inoculation of the healthy subject varied in seven cases from 

 two to eight days and in the remaining two from ten to thirteen days, 

 whereas in two of the three successful cases the mosquito had been kept 



