"The deviation of the Cow Pox from its true character appears to be very frequent; and when it does appear, it is, as far as I have seen, uniformly in the following manner: The vesicle, instead of bein…"

"You see by the papers how I'm annoyed by a set of blockheads who write about the imperfection of the cowpox, as a vaccine, without any knowledge scarcely of its phenomena."

"I have often been surprised at the credulity of mankind; but I have also been surprised at their obstinacy."

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

"The path of discovery is not a smooth one; it is often beset with difficulties and discouragements."