John Coakley Lettsom (1744–1 Nov 1815) was an English physician and philanthropist. He was born on Little Jost Van Dyke in the British Virgin Islands, into one of the early Quaker settlements in the territory, and he grew up to be an abolitionist. His surname is sometimes spelled Lettsome.
Lettsom founded the Medical Society of London in 1773, convinced that a combined membership of physicians, surgeons, and apothecaries would prove productive. His revolutionary idea met with success and the Society has provided a forum for all branches of the medical profession from its inception to the present. Situated at the heart of London's medical community at Lettsome House, Chandos Street, near Cavendish Square, this is the oldest medical society in the United Kingdom.
As founder, president (1775–76, 1784–85, 1808–11, 1813–15), and benefactor Lettsom was the mainstay of the Society from 1773 until his death in 1815.
John Coakley Lettsom was born into the Quaker community on the island of Little Jost Van Dyke in the British Virgin Islands, in 1744. John and his brother were the sole survivors of seven sets of male twins, sons of Edward and Mary Lettsom. John alone was sent to England at the age of six to be educated.
At school in Lancashire the antics of the young Lettsom attracted the attention of the Quaker preacher Samuel Fothergill, who introduced his protégé to his brother, the London physician, Dr John Fothergill. Having completed an apprenticeship to a Yorkshire apothecary, Lettsom came to London in 1766 when, through the influence of Dr Fothergill, he commenced his medical training at St Thomas' Hospital. His studies were interrupted by the death of his father, prompting his return to Tortola in the British Virgin Islands where he freed the slaves he had inherited and provided medical care for the local population. As the only doctor in the islands at that time, he was able to earn a considerable sum. Diligence and industry earned him a fortune, enabling him to resume his studies in Europe. John Coakley Lettsom matriculated at the Leyden University 8 June 1769 He received his Medical Doctor degree 20 Juni 1769. His thesis concerns the natural history of the tea-tree. The title description of his thesis is: Dissertatio inauguralis medica, sistens Observationes ad vires theae pertinentes. Quam … pro gradu Doctoratus summisque in Medicina Honoribus & Privilegiis, ritè ac legitimè consequendis, eruditorum examini submittit Joannes Coakley Lettsom, Tortola – Americanus. Ad diem XX. Junii MDCCLXIX. H.L.Q.S. - Lugduni Batavorum : apud Theodorum Haak, 1769. - 24 p. (interleaved)  l. ; 24 cm.
Lettsom was also a close friend of Benjamin Franklin and William Thornton.
Lettsom's career accelerated with the LRCP and marriage to an heiress. By the age of 30 his reputation as a physician, author, and Fellow of the Royal Society was established. Furthermore, he had founded the General Dispensary in Aldersgate Street and the Medical Society of London. He was a founder-member of the Royal Humane Society in 1774, he initiated the Sea-bathing Infirmary at Margate (1791), became a pillar of the Royal Jennerian Society (for vaccination) and gave his support to the Society for the Relief of Widows and Orphans of Medical Men, the Society for the Relief of Debtors, and the Philanthropic Society (for homeless children). Numerous clubs, societies, hospitals, dispensaries, and charitable institutions in the United Kingdom and North America benefited from Lettsom's patronage, while from his pen there flowed a stream of "Hints", pamphlets, diatribes, and letters promoting Sunday schools, female industry, provision for the blind, a bee society, soup kitchens and the mangel-wurzel, and condemning quackery, card parties, and intemperance. In the diversity of his interests, as physician, philanthropist, botanist, mineralogist and collector, Lettsom was in the mould of that giant of the previous generation of London physicians, Sir Hans Sloane.
As founder, President (1775–76, 1784–85, 1808–11, 1813–15) and benefactor of the London Medical Society, Lettsom was the mainstay of the society from 1773 until his death in 1815. His influence remained strong and his example inspired the next generation of Fellows—men such as Dr Thomas Pettigrew, his biographer, and Dr Henry Clutterbuck, who followed in Lettsom's footsteps as President of the Society and physician to the General Dispensary. In 1791 Lettsom won the society's Fothergillian prize for a treatise entitled Diseases of Great Towns and the Best Means of Preventing them.
He was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1788.
For at least a portion of his years working in London, he lived in Newington Green, a village full of English Dissenters clustered around a green and its Unitarian church. There he met the young Mary Wollstonecraft and others intent on social reform.
Lettsom is reported to have written about himself:
I, John Lettsome, Blisters, bleeds and sweats 'em. If, after that, they please to die, I, John Lettsome.
Richard Woodman attributes similar words to the fictional naval surgeon Mr. Lettsom in The Bomb Vessel:
When people's ill, they come to I, I physics, bleeds and sweats 'em; Sometime they live, sometimes they die,
What's that to I? I let's 'em.
Lettsom was also a noted abolitionist. In 1767 he had returned to the British Virgin Islands after the death of his father, and found himself the owner of a share of his father's slaves, whom he promptly manumitted. Lettsom then set up a medical practice on Tortola, and as the only physician on the island amassed a veritable small fortune of £2,000 in a mere six months, whereupon he gave half to his mother (who had remarried) and returned to London.
When his good friend, William Thornton, sought his advice about setting up a colony for freed slaves on the west coast of Africa, Lettsom counseled against it, and suggested that spending the money acquiring and manumitting the slaves in North America would be a better use of funds.
However, towards the end of his life, something ironic happened. Lettsom's son, Pickering Lettsom, returned to Tortola to practice law, and there he married a wealthy widow, Ruth Georges née Hodge, who had inherited some 1,000 slaves from her grandfather, Benzaliel Hodge. Pickering Lettsom died about a month after the marriage, and his new wife (some 16 years his senior) died a few months later on the 21 Jan 1809, and left all of her property to her father-in-law, John Lettsom. By a twist of fate, shortly before his own death, Lettsom, who had freed all the slaves he had ever owned, found himself as the owner of another 1,000 slaves. However, Lettsome himself died before he had a chance to decide what to do with the slaves, and they were inherited by his grandson William Pickering Lettsom.
Lettsom was an entomologist. He wrote The naturalist's and traveler's companion, containing instructions for collecting and preserving objects of natural history and for promoting inquiries after human knowledge in general. London: E. and C. Dilly (1774)a much used work.