University of Virginia Library

8772. VACCINATION, Utility of.—

I am happy to see that vaccination is introduced,
and likely to be kept up, in Philadelphia; but
I shall not think it exhibits all its utility until
experience shall have hit upon some mark or
rule by which the popular eye may distinguish
genuine from spurious virus. It was with this
view that I wished to discover whether time
could not be made the standard, and supposed,
from the little experience I had, that matter,
taken at eight times twenty-four hours from the
time of insertion, could always be in the proper
state. As far as I went I found it so; but I
shall be happy to learn what the immense field
of experience in Philadelphia will teach us on
that subject.—
To Dr. Benjamin Rush. Washington ed. iv, 425. Ford ed., viii, 126.
(W. Dec. 1801)