From the arm of this girl matter was taken and inserted April 12th into the arms of John Marklove one year and a half old,

Robert F. Jenner, eleven months old,
Mary Pead, 5 years old, and
Mary James, 6 years old.

Among these Robert F. Jenner did not receive the infection. The arms of the other three inflamed properly and began to affect the system in the usual manner; but being under some apprehensions from the preceding Cases that a troublesome erysipelas might arise, I determined on making an experiment with the view of cutting off its source. Accordingly after the patients had felt an indisposition of about twelve hours, I applied in two of these Cases out of the three, on the vesicle formed by the virus, a little mild caustic, composed of equal parts of quick-lime and soap, and suffered it to remain on the part six hours[1]. It seemed to give the children but little uneasiness, and effectually answered my intention in preventing the appearance of erysipelas. Indeed it seemed to do more, for in half an hour after its application, the indisposition of the children ceased[2]. These precautions were perhaps unnecessary as the arm of the third child, Mary Pead, which was suffered to take its common course, scabbed quickly, without any erysipelas.

1: Perhaps a few touches with the lapis septicus would have proved equally efficacious.

2: What effect would a similar treatment produce in inoculation for the Small-pox?