Born at Stockton-on-Tees, the son of John Tweedy, a solicitor. He was educated at Elmfield College, York, and at University College, London, from which he went to University College Hospital for his medical course. He qualified in 1872, and in 1873 became a Clinical Assistant at the Royal London Ophthalmic Hospital, Moorfields, thus beginning a long and distinguished association with that institution. Tweedy was never a robust man, and always suffered from an embarrassment of respiration, a wheeziness, the nature of which was obscure. It is said that his frail physique determined Tweedy not to attempt the career of general surgery and led him to become an ophthalmic surgeon. In this line he soon showed himself something above the ordinary, by his work, his early publications and his wide interest in the whole field of medicine. At Moorfields he was appointed Assistant Surgeon in 1877 on the resignation of Sir Jonathan Hutchinson (q.v.), Surgeon in 1878, Consulting Surgeon in 1900, when he was placed upon the Committee of Management in recognition of the "numerous occasions he had pleaded the cause of the Hospital in powerful and most interesting public addresses, endorsing his advocacy with liberal donations to its funds". He was likewise appointed Ophthalmic Surgeon to the Great Northern Hospital in 1878, Assistant Ophthalmic Surgeon to University College Hospital in 1881, and Professor of Ophthalmic Medicine and Surgery in University College. In addition to his professional work, Tweedy was interested in music, politics, books, history, and journalism. He was the editor of the "Mirror of Hospital Practice" in the *Lancet* and became the close friend of Dr. James Wakley, the editor of that journal, for which he was a constant leader-writer. The centenary number of the *Lancet* speaks of his being offered the editorship and refusing it. It is said that he was largely responsible for the utterance of the editorial views of the *Lancet* on the constitution of the Royal College of Surgeons, and it was as a reformer that Tweedy stood for and was elected to a seat on the Council in 1892. Here, however, he expressed moderate views and gained for himself the warm friendship and hearty co-operation of the leaders of the medical profession, so much so that in 1903 he was elected President of the College, and retained office for three years, being succeeded in 1906 by Sir Henry Morris (q.v.); in his final year as President (1906) he received the honour of knighthood. Tweedy was the first surgeon practising purely as an ophthalmologist to obtain the presidency of the College, and during his term of office he gave the presidential badge to the College to be worn by future Presidents when in their robes of office. While President of the College, Tweedy was also President of the Ophthalmological Society of the United Kingdom, President of the Medico-Legal Society, of the Medical Defence Union, and of the Royal Medical Benevolent Fund. He took an active share in King Edward's Hospital Fund, serving on the Distribution Committee, for which his powers of organization peculiarly fitted him. He was admitted to the Livery and Court of the Barbers' Company, where he was chosen Master and thus brought about a *rapprochement* between the Company and the College of Surgeons. The Barbers' Company having founded the Vicary Lectures at the Royal College of Surgeons, he was appointed to deliver the first lecture in December, 1919, when he chose as his subject "Surgical Tradition". Tweedy was an excellent speaker, whether in a set lecture or after dinner. He showed precision, making his points deliberately, and his speeches were always imbued with a kindliness and modesty which were characteristic of the man. In 1905 he was Hunterian Orator, and in his later years one of the Hunterian Trustees. On the occasions when the Hunterian Trustees met at the College, the sound of his horses' hoofs might be heard with measured tat-tat in front of the portico, for Sir John was perhaps the last consulting surgeon in London to keep a brougham instead of a car. Almost immediately afterwards a measured but laboured breathing announced the arrival at the door of the Librarian's room of Sir John himself, who, after making his courteous old-world greetings, would proceed to the discussion, and nearly always the presentation of valuable books, for which benefactions the Library is grateful. He lived at 100 Harley Street, where he had a large library of some 6000 volumes. By his will he bequeathed to the Royal College of Surgeons such of his medical and surgical books and instruments as the College might select, and to University College Hospital Medical School any others to be selected by that body after the College had made its choice. He left over £61,000, ultimate residue as to one-half, after other bequests, to go to the College in case of the failure of his heirs. In 1895 Tweedy married the daughter of Mr. Richard Hillhouse, of Finsbury Place, and left two sons and one daughter. He died on Jan. 4th, 1924, after a short illness following an operation, and his ashes were interred at Holder's Green Crematorium on Jan. 8th. Though Tweedy published no large work he had written a great deal, as the following list of his publications shows. Possibly his best-known original observation was that the physiological 'lens star' could be recognized clinically. He also advanced a theory as to the causation of conical cornea being due to developmental defect and brought the idea before the Ophthalmological Society of the United Kingdom, in whose *Transactions* (xii, 67) it appears. He was also a pioneer in practising the extraction of immature cataracts. There are several portraits of him in the College Library, the largest a photograph from a portrait by Frank B. Salisbury. PUBLICATIONS: "On a Visible Stellation of the Normal and of the Cataractous Crystalline Lens of the Human Eye," - *Royal London Ophthal. Hosp. Rep.*, 1876, viii, 24. This paper, accompanied by drawings, attracted a good deal of attention and was a sequel to one published in the *Lancet*, 1871, ii, 776. "On an Improved Optometer for Estimating the Degree of Abnormal Regular Astigmatism," 8vo, illustrated, London, 1876; reprinted from *Lancet*, 1876, ii, 604. "Treatment of Hardness of the Eyeball by Mydriatics and Myotics." *Practitioner*, 1883, xxxi, 321. "On an Improved Optometer for Estimating the Degree of Astigmatism and other Errors of Refraction." *Lancet*, 1886, i, 777. "On the Meaning of the Words 'Nyctalopia' and 'Hemeralopia' as disclosed by an Examination of the Diseases described under these Terms by the Ancient and Modern Medical Authors," 12mo, London, 1882; reprinted from *Royal London Ophthal. Hosp. Rep*., 1882, x, 413. "On a Case of Large Orbital and Intracranial Ivory Exostosis," 8vo, London, 1882; reprinted from *Royal London Ophthal. Hosp. Rep.,* 1882, x, 303. "An Inaugural Address delivered in University College, London, on October 1st, at the Opening of the Session 1883-4," 8vo, London, 1883; reprinted from *Lancet*, 1883, ii, 577. "Lectures on the Ætiology of Constitutional Diseases of the Eye," 12mo, London, 1887; reprinted from *Lancet*, 1887, i, 57. "Extraction of Immature Cataract." - *Lancet*, 1888, i, 966, "On Some Phases of the Constitutional History of the College of Suregons," 8vo, London, 1889; reprinted from *Lancet*, 1889, i, 957, 1112. "On Cicatricial Ectropion of the Lower Lid following Caries of the Orbit," 8vo, illustrated, London, 1890; reprinted from *Ophthal. Soc. Trans.*, 1890, x, 211. "The Physical Factor in Conical Cornea," 8vo, London, 1892; reprinted from *Ophthal. Soc. Trans*., 1892, xii, 67. "The Relation of Ophthalmology to General Medicine and Surgery and to Public Health" (Presidential Address to the Ophthalmological Society of the United Kingdom), 8vo, London, 1904; reprinted from *Ophthal. Soc. Trans.*, 1904, xxiv, 1. *A Clinical Lecture on the Forms of Conjunctivitis, with Special Reference to the Treatment of Ophtalmia Neonatorum*, 8vo, London, 1895. *An Address delivered by the President of the Royal College of Surgeons of England in Norwich Cathedral on the Occasion of the Unveiling of the William Cadge Memorial Window on the 6th of December,* 1904. *The Hunterian Oration delivered at the Royal College of Surgeons of England on the 14th of February, 1905,* 8vo, London, 1905. *An Address to Medical Students delivered at University College Hospital Medical School on the 1st of October, 1909, on the Occasion of the Opening of the Winter Session,* 8vo, London, 1909. "Presidential Address on the Influence of Social and Legal Restrictions on Medical Practice. Delivered before the Medico-Legal Society on the 25th October, 1910," 8vo, London, 1910; reprinted from *Medical Mag*., 1910, xix, 701. "The Mutual Relations and Influence of Law and Medicine. A Presidential Address," 8vo, London, 1910; reprinted from *Trans. Medico-Legal Soc*., 1910, vii, 1. *The Medical Tradition; being the Annual Oration delivered before the Medical Society of London on May 12th*, 1919, 8vo, London, 1920. *The Surgical Tradition; being the First Thomas Vicary Lecture delivered before the Royal College of Surgeons of England, on December 3rd*, 1919, 8vo, London, 1920. "Eyelids," "Cornea," and "Sclerotic," in Heath's *Dictionary of Practical Surgery*. "Cataract," "Hemeralopia," "Nyctalpoia," and "Pupil," in Quain's *Dictionary of Medicine*, "Diseases of the Skin" in Roberts's *Text-book of Medicine*.