Edward Jenner as Naturalist. 
67 
have found necessary nor taken. It was only by recognizing 
every successive phase of Jenner’s inquiry, each in its turn 
dependent upon that preceding, that Dr. Waterhouse was 
enabled to experiment in retro-vaccination, the transference 
of humanized virus, attenuated by long-continued trans¬ 
mission, back to the cow, in the hope of regaining its orig¬ 
inal certainty and potency; and that, far more effective and 
successful still, the late Dr. Henry A. Martin, of Boston, 
followed by Depaul, conceived the idea of vaccinating di¬ 
rectly from a spontaneous case in the cow, to other unaffected 
individuals in the same or different herds. This heifer- 
to-heifer transmission, from the Beaugency and other stocks, 
is now practised throughout the world. “ In the first year 
after vaccination was announced,” says Martin (Journal of 
the Gynaecological Society of Boston, Vol. VII.), “every en¬ 
lightened physician in Christendom was up to his ears in 
vaccine experimentation. Every sort of animal from the 
elephant to the mouse was vaccinated, and even birds. 
Among thousands of such experiments there were none in 
which the end sought was the perpetuation of the disease 
originally occurring in the cow, in similar animals, without 
passing through a single human system.” 
Jenner had remarkable patience. The persistence of this 
we have noticed throughout his life. 
He could be wisely silent. Although the object of many 
unkind and unfair criticisms, he never would weaken the 
strong position which the truth had enabled him to take, 
by replying to them. 
He had the strongest self-control. He once silenced a 
noble lord, a friend of one of his defamers, who ignorant 
of his presence was railing most scurriously at vaccination, 
by simply confronting him and saying, “Your Lordship, I 
am Dr. Jenner.” 
He had the courage of his convictions. Sir Humphrey 
Davy relates that he was once discussing with Jenner, in 
1799, the uses of earthworms to man. Sir Humphrey con¬ 
sidered the dung-hill and putrefaction far more useful to 
