He was, moreover, the intellectual father of that interesting group of men on this side of the Atlantic who, while practising as physicians, devoted much time and labor to the study of natural history; such men as Benjamin Smith Barton, David Hossack, Jacob Bigelow, Richard Harlan, John D.Godman, Samuel George Morton, John Collins Warren, Samuel L.Mitchill and J.Ailken Meigs.

He gave an immense impetus in Great Britain to the study of morbid anatomy, and his nephew, Matthew Baillie, published the first important book on the subject in the English language.
Before the eighteenth century closed practical medicine had made great advance.

Smallpox, though not one of the great scourges like plague or cholera, was a prevalent and much dreaded disease, and in civilized countries few reached adult life without an attack.

Edward Jenner, a practitioner in Gloucestershire, and the pupil to whom John Hunter gave the famous advice: "Don't think, try!" had noticed that milkmaids who had been infected with cowpox from the udder of the cow were insusceptible to smallpox.

I show you here the hand of Sarah Nelmes with cowpox, 1796.