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

"I shall endeavor still further to prosecute this inquiry, an inquiry I trust not merely speculative, but of sufficient moment to inspire the pleasing hope of its becoming essentially beneficial to man…"

"I have often found that the best way to learn is to teach."

"I have often been struck with the wonderful harmony that prevails throughout the works of nature."

"The disease has hitherto been confined to particular districts; and it has been observed, that where the Cow Pox has prevailed, the Small Pox has been much less frequent, and much less fatal."