Edward Jen tier as Naturalist. 
61 
the degree of Doctor of Medicine from the University of St. 
Andrews The time was rapidly ripening for the comple¬ 
tion and announcement of his discovery. It is, indeed, not 
unlikely that he had been consciously waiting for this diplo¬ 
ma of full physician, which would enable him to speak to 
all other physicians as one having their own authority. 
In 1793 published “A Process of Preparing Pure 
Emetic Tartar by Recrystallization,” in the first volume of 
the Transactions of the Society for the Improvement of Medi¬ 
cal and Chirurgical Knowledge. It is of interest as showing 
that his proficiency in pharmacy, of which mention has al¬ 
ready been made, was based not only upon medical botany 
and the commercial peculiarities of drugs, but upon chem¬ 
istry also. 
In 1794 he was seriously ill with typhus, or true jail or 
ship-fever, which was then a not uncommon and very fatal 
disease. During this year he was still continuing his obser¬ 
vations upon kine-pox. In 1795, still sounding persistently 
the same string, he experimented upon his own son, then 
a child of six, whom he had previously inoculated with 
swine-pox also. One year more, and the crucial test came, 
the great discovery, of the practicability and certainty of 
which he had so long been convinced. Upon May 14, 1796, 
he vaccinated a boy of eight, James Phipps, from the hands 
of a milkmaid, Sarah Nelmes, who had been infected by 
her master’s cows. The boy passed the successive stages 
of the disease satisfactorily, and on July 1st was inoculated 
for small-pox without the slightest effect. It was done to 
him again and again, the result being the same. From 
this time forward he made the most extensive experiments 
with uninterrupted success. He had ascertained, beyond the 
possibility of doubt, that humanized cow-pox was in its 
earlier removes as efficacious, and could with as great ease 
and certainty be conveyed from one human being to another, 
as the original cow-pox itself, which, as has been stated, it 
was at times impossible to procure. He subsequently found 
that it was only at a certain stage of the disease that the 
virus could usefully, or even safely, be taken. 
