1To Thomas Jefferson from Benjamin Waterhouse, 8 June 1801 (Jefferson Papers)
...our object through a mist.” My insulated situation, and remoteness from all correct information on this head, has compelled me to the closest observation of the progress of the pustule, even from hour to hour, with the microscope; and I am convinced of the importance of Dr. Jenner’s injunctions to me; nay more, I am convinced by my own blunders.
2To Thomas Jefferson from Benjamin Waterhouse, 2 September 1801 (Jefferson Papers)
...than the 9th. The efflorescence is a sign that the absorption has commenced, and the nicety of the business is to take the virus just before that period. I have watched this process with a microscope in a number of persons whom I had taken into my house for this express purpose, and experience has now taught me a sure procedure, somewhat different from my early theory, which was to...