Sutcliffe did not find his new apprentice a very handy one. "Thou mayest make a physician, but I think not a good apothecary," the old man was in the habit of saying; and the prediction in due course turned out a correct one. Having served an apprenticeship of five years, and walked for two the wards of St. Thomas's Hospital, where Akenside was a physician, conspicuous for supercilious manner and want of feeling, Lettsom returned to the West Indies, and settled as a medical practitioner in Tortola. He practised there only five months, earning in that time the astonishing sum of £2000; when, ambitious of achieving a high professional position, he returned to Europe, visited the medical schools of Paris and Edinburgh, took his degree of M.D. at Leyden on the 20th of June, 1769, was admitted a licentiate of the Royal College of Physicians of London in the same year, and in 1770 was elected a fellow of the Society of Antiquaries. From this period till his death, in 1815 (Nov. 20), he was one of the most prominent figures in the scientific world of London. As a physician he was a most fortunate man; for without any high reputation for professional acquirements, and with the exact reverse of a good preliminary education, he made a larger income than any other physician of the same time. Dr. John Fothergill never made more than £5000 in one year; but Lettsom earned £3600 in 1783--£3900 in 1784--£4015 in 1785-and £4500 in 1786. After that period his practice rapidly increased, so that in some years his receipts were as much as £12,000. But although he pocketed such large sums, half his labours were entirely gratuitous. Necessitous clergymen and literary men he invariably attended with unusual solicitude and attention, but without ever taking a fee for his services. Indeed, generosity was the ruling feature of his life. Although he burdened himself with the public business of his profession, was so incessantly on the move from one patient to another that he habitually knocked up three pairs of horses a-day, and had always some literary work or other upon his desk, he nevertheless found time to do an amount of labour, in establishing charitable institutions and visiting the indigent sick, that would by itself have made a reputation for an ordinary person.