Annual Address by the President. 
9 
London; 1774, Jesty, a Dorsetshire farmer; 1791, Pless, a Holstein 
teacher, and May 14, 1796, Jenner, confirmed these observations. 
It is true that the immortal work of Jenner began as early as the 
year 1769, for at that time, while a student under John Hunter, 
he heard a young country-woman, in whose presence the subject 
of smallpox was mentioned, say : '“I can not take that disease, for 
I have had eowpox.” Upon mentioning the subject to his master, 
Hunter replied: “Do not think, lout try ; be patient , be accurate ” 
Jenner did try; was patient, was accurate; and on May 14, 1796, 
after years of patient labor, in his “Inquiry into the Causes and 
Effects of the Yariolae Vaccinae,” 2 he experimentally established 
the following facts: 
“(1) That this disease (eowpox) casually communicated to 
man has the power of rendering him unsusceptible of smallpox. 
“(2) That the specific eowpox alone, and not other eruptions 
affecting the cow, which might be confounded with it, had this 
protective power. 
“(3) That the eowpox might be communicated at will from the 
cow to man hy the hand of the surgeon, whenever the requisite 
opportunity existed; and 
“(4) That the eowpox once ingrafted on the human subject 
might be continued from individual to individual by successive 
transmissions, conferring on each the same immunity from small- 
pox as was enjoyed by the one first infected direct from the cow/" 
Thus it is seen that Jenner, by inoculating a cow with variolus 
matter produced in the cow an eruptive disease resembling small- 
pox, but of a milder type, and that the cultivation of this milder 
disease in the cow yielded a fixed virus (vaccine) which, trans- 
planted to man gave rise to a still milder eruptive disease (vac- 
cinia) possessing constant characteristics, and conferring upon per- 
sons who underwent it immunity against smallpox. 
The older methods of inoculation against smallpox were quickly 
supplanted by the simpler and far safer method of vaccination; 
and since the introduction of the latter the appalling ravages of 
smallpox have been relegated to historical literature. 
The subsequent development of vaccination is a matter of such 
general information there is no need of its further discussion here. 
It is sufficient to say that in the great majority (if not in all) of 
the cases of successful vaccination immunity against smallpox is 
conferred for an indefinite period, varying from three years to 
many years — averaging three to seven years — in some cases for 
life; and that compulsory vaccination and revaccination offers the 
safest and surest protection against this loathsome disease. 
