Francis Sacheverel was a son of Erasmus Darwin and his second wife Elizabeth (née) Collier, widow of Col Edward Pole and natural daughter of Charles Colyear, 2nd Earl of Portmore.

The diary of the tour shows a keen antiquarian taste gratified under many difficulties, and it is recognised that Darwin not only loved adventure for its own sake, but was a born naturalist also, whose ready pencil followed a keen eye, where rock and mineral, plant and beast were concerned, as readily as when it portrayed an archaeological novelty or displayed the costumes of Greece or Turkey.

Darwin, wanting more experience of the plague, on another return to Smyrna undertook by invitation of the native physicians charge of several hospitals, of which the Greek and Armenian contained each 120 patients.

This was a good opportunity to become conversant, with the diseases of the climate, and from constant observation I found the plague was frequently checked by an active practice of which the Medici of the East were totally ignorant.

He transmitted his love of natural history to his son Edward Levett Darwin, author (under the name of "Hugh Elms") of a 'Gamekeeper's Manual' (4th edition 1863), which shows keen observation of the habits of various animals.