ble that
a disease of so peculiar a nature as the Cow Pox, which has appeared
in this and some of the neighbouring counties for such a series of
years, should so long have escaped particular attention. Finding the
prevailing notions on the subject, both among men of our profession
and others, extremely vague and indeterminate, and conceiving that
facts might appear at once both curious and useful, I have instituted
as strict an inquiry into the causes and effects of this singular
malady as local circumstances would admit.

The following pages are the result, which, from motives of the most
affectionate regard, are dedicated to you, by

Your sincere Friend,
EDWARD JENNER.

Berkeley, Gloucestershire,
June 21st, 1798.

AN INQUIRY, _&c. &c._

The deviation of Man from the state in which he was originally placed
by Nature seems to have proved to him a prolific source of Diseases.
From the love of splendour, from the indulgences of luxury, and from
his fondness for amusement, he has familiarised himself with a great
number of animals, which may not originally have been intended for
his associates.

The Wolf, disarmed of ferocity, is now pillowed in the lady's lap[1].
The Cat, the little Tyger of our island, whose natural home is the
forest, is equally domesticated and caressed. The Cow, the Hog, the
Sheep, and the Horse, are all, for a variety of purposes, brought
under his care and dominion.

There is a disease to which the Horse, from his state of
domestication, is frequently subject. The Farriers have termed it
_the Grease_. It is an inflammation and swelling in the heel, from
which issues matter possessing properties of a very peculiar kind,
which seems capable of generating a disease in the Human Body (after
it has undergone the modification which I shall presently speak of),
which bears so strong a resemblance to the Small Pox, that I think it
highly probable it may be the source of that disease.

In this Dairy Country a great number of Cows are kept, and the office
of milking is performed indiscriminately by Men and Maid Servants.
One of the former having been appointed to apply dressings to the
heels of a Horse affected with _the Grease_, and not paying due
attention to cleanliness, incautiously bears his part in milking the
Cows, with some particles of the infectious matter adhering to his
fingers. When this is the case, it commonly happens that a disease is
communicated to the Cows, and