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This case, however, as well as a few others among my 104 inoculated 

 subjects (1881 to 1900), merely shows that the rules set down by Drs. 

 Reed, Carroll and Agramonte are not so absolute as they have imagined. 

 With this reservation, I have no hesitation in admitting that the general 

 principle which they discovered and which, in their hands, has given 

 such brilliant residts, is the right one to work upon, especially when it is 

 desired to contaminate the insect with only one bite upon a mild ease and 

 within the first days of the attack. It is more than likely, indeed, that the 

 average time required for the complete contamination of the mosquitoes 

 will be found to vary at different seasons of the year, and I feel certain 

 that, when this point comes to be investigated, the minimum in summer 

 will occasionally be found reduced to a limit as low as two days for the 

 interval between the initial contamination and the date in which the 

 insect may already be in a condition to reproduce a mild attack of the 

 disease; in such cases, too, the period of incubation, according to my 

 personal observations, is apt to extend beyond its usual limits of two 

 to eight days. This circumstance may, perhaps, be accounted for on the 

 supposition that the quantity of virulent germs inoculated in such cases 

 go through any special transformation within the body of the insect ; 

 my idea was simply that the prolonged contamination would allow 

 has been so small that a prolonged incubation becomes necessary before 

 their number can reach a figure which is capable of developing the outbreak 

 of an attack. This diversity in the period of incubation might be consi- 

 dered another point of analogy between the yellow fever germ and the 

 malarial parasite. Major Ronald Ross himself having declared that "there 

 is a well known period of incubation" (after the bite of the malaria-mos- 

 quito) "lasting from two days up to twenty or even longer — the usual 

 period being one or two weeks." 



160 Campanario Street. 



