MS (Roger W. Barrett, Chicago, 1947); entirely in TJ’s hand; on verso of the list of inoculations of 7 Aug.-17 Sep. 1801 (Vol. 35:34–5), and on the same sheet as lists of vaccinations dated April-May 1816 and 17 Mch. 1826.

One method of preserving the cowpox vaccine for later use was by drawing a THREAD through a pustule on the skin of a person who had been successfully vaccinated; see Vol. 35:8, 120–1, 170, 174, 604, 680. The list printed above indicates that TJ succeeded in inoculating JOHN PERRY with vaccine from a thread on 10 May. Nine days later TJ probably used fluid directly from an eruption on Perry’s skin to vaccinate others, including at least two people whose vaccinations from the thread on the 10th had failed, John Hemings and the woman identified only as HENRIETTA. On 26 May, TJ continued the cycle by vaccinating a dozen more people, probably from pustules of individuals he had vaccinated on the 19th. TJ and Benjamin Waterhouse had found in 1801 that fluid from pustules was most effective about eight days after inoculation (same, 34–5, 166, 198, 213, 278; Waterhouse to TJ, 29 Jan. 1802).