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the yellow-fever infection. The germs would multiply in the body of the 

 insect and finally invade its salivary and venom glands, so that they would 

 be discharged with the secretions of those glands along the track of the 

 wound and into the capillary vessel entered by the sting when the insect 

 attacked its next victim (see Medical Record, May 27th, 1899). 



3. I had satisfied myself, as a result of my long-continued experiments 

 with contaminated mosquitos applied (one or two at a time) not later than 

 from two to five days after the insects had bitten a patient with yellow 

 fever, that it was useless to attempt to contaminate these mosquitos from 

 mild cases. I concluded: (a) that this procedure, in the summer season, 

 sometimes develops a mild attack, similar to some of the experimental cases 

 recently elicited by the more perfect methods adopted by Dr. Reed and his 

 colleagues: (b) much oftener, however, (in the proportion of six or seven 

 to one) the aforesaid procedure fails to develop any perceptible pathogenic 

 effects, even though the subsequent histories of the inoculated persons had 

 left no doubt in my mind but that most of them had thereby acquired a 

 complete or a partial immunity, enabling them to withstand subsequently 

 severe exposures to the yellow- fever infection, either without becoming 

 themselves infected, or contracting only such mild forms as some experts 

 are loth to recognize as genuine yellow fever. 



4. Since 1891, I had been convinced, from a careful study of Melier's 

 report on the St. Nazaire epidemic, that by extending the interval between 

 the contamination of the mosquito and the inoculation of a non-immune to 

 more days or weeks, instead of the two to five days' limit which I had 

 adopted, I should run the risk of developing a severe or a fatal attack, such 

 as I was particularly anxious to avoid (see Medical Record, January 19, 

 1901). 



5. In view of some belated cases of yellow fever which had come under 

 my notice and were difficult to reconcile with the limit of thirty-five to 

 forty days during which I had been able to keep my mosquitos alive, I was 

 induced to suggest that the issue of an infected mosquito (developed from 

 eggs which had traversed the infected cloaca) might, possibly, be also 

 capable of reproducing the disease (see Medical Record, May 27, 1890). 

 The necessity for this additional factor, however, has now, in a great 

 measure, disappeared since Dr. Carroll's success in keeping the infected 

 mosquitos alive during periods of seventy and seventy-one days. It is, 

 nevertheless, a point which deserves to be further investigated, notwith- 

 standing the negative result in Dr. Reed's only trial, and also in one of 

 my own. 



Dr. Reed's persistence in discrediting my positive experimental results, 

 as explained in Proposition 3 (a), is all the more extraordinary from the 

 fact that the experiments made by his colleagues and himself, upon those 

 lines, with mosquitos which had bitten a person with a severe or fatal form 

 of the disease only a few days before the inoculation, have been very few 



