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its results in order to bring over to their views the balance of scientific 

 opinion and public favor. They represent, moreover, two distinct applic- 

 ations of that method. Jenner vaccinated indiscriminately a vast number 

 of subjects in order to verify subsequently the immunity enjoyed by the 

 majority when exposed to the variolous infection. Pasteur, on the other 

 hand, adopted the system of carefully registering every person inoculated 

 by his method after being bitten by a rabid animal, and afterwards compar- 

 ing the statistical results observed in them with the average proportion of 

 hydrophobic cases developed in the noninoeulated after similar bites. I have 

 chosen Pasteur's plan, believing it to be the more reliable and more applic- 

 able to our case. It cannot be denied, however, that, limited as we have 

 been in our field of experiment, our numbers cannot compare with those 

 of the glorious French investigator, and that we labor under a disadvantage 

 in having to deal with a disease which so far has not been proved to 

 occur, under ordinary circumstances, in lower animals. Thus obliged to 

 confine our investigations to the human species, it could hardly be ex- 

 pected of us that we should carry our scientific zeal to the point of seeking, 

 through a bolder application of our inoculations, to determine a violent 

 attack of the disease, thereby carrying conviction, no doubt, to the sceptical 

 mind, but at the risk of having betrayed the confidence placed in us. 



A somewhat specious objection was recently raised against our mosqui- 

 to-inoculations, on the plea that the proboscis of the insect, not being suscept- 

 ible of sterilization many accidental germs might be inoculated together 

 with or instead of those of yellow fever, supposing the latter to exist in 

 the probocis of the contaminated mosquito. To this hypothetical imputa- 

 tion I can oppose many facts. In none of our numerous inoculations has 

 such an occurrence been observed, nos has it ever been proved that the 

 acclimated inhabitants who are constantly being stung by those insects 

 acquire thereby any specific infection. I have on several occasions introd- 

 uced into sterilized tubes provided with agar jelly mosquitoes that had 

 stung acclimated persons. In most of these experiments, after several days' 

 confinement, the insect died for want of food, and yet not a single colony 

 appeared upon the jelly; when any growth was developed it mostly 

 consisted of fungi, the spores of which had probably been introduced acci- 

 dentally while transferring the insect from one tube into another. From 

 this curious result I infer that the insect has some means of rendering its 

 outer surface aseptic, and probably does so through a very peculiar 

 operation which I have often seen it perform. This consists in collecting 

 with its hind or middle legs a secretion expelled from the posterior part of 

 its body, and besmearing very persistently with it every part of its body,legs. 

 wings head, and proboscis. I also believe that we are justified in admitting 

 that the liquid which the insect employs to lubricate its complicated sting, 

 and which being poured into the wound occasions the painful sensation felt 



