"The cow-pox is a mild disease, and never fatal; the small-pox is a formidable one, and often fatal. The cow-pox is not infectious; the small-pox is highly so."

"I have been so much engaged in making experiments, that I have had no time to write letters."

"Altho' I should be happy to shield it myself from the speckled Monster, yet I would advise you not long to risk my coming to Town. I will just add that I consider the Vaccine Lancet in the hand of [Dr…"

"How wonderful that this horrid pestilence should at this time even have an existence in our island . . . A Physician from Copenhagen call'd on me today, and express'd his astonishment at an opposition…"

"The pursuit of knowledge is an endless one; but it is also a most delightful one."