Became a member of the Staff of the Royal Free Hospital early in life, but in the absence of a medical school there, he joined the Grosvenor Place School of Medicine, where for a time he held the post of Lecturer on the Principles and Practice of Medicine. His colleagues here were Spencer Wells, B Ward Richardson, and William Adams. He then specialized in diseases of the chest, and was appointed Physician to the Margaret Street Infirmary for Consumption and to the City Dispensary. At the Royal Free Hospital he was for many years Senior Physician. He had numerous valuable drawings made of patients suffering from aneurysm of the root of the neck, and in his researches found the record of two cases of apparent cure of aneurysm of the arch due to obliteration of the left carotid. When Christopher Heath (qv) used distal ligature in 1865, Cockle became still more convinced that this method offered relief in aortic aneurysm, and in 1872, a suitable case presenting itself in his practice, he induced Heath to tie the left carotid in the neck. The patient made a complete recovery and lived for four years. The specimen is in the College of Surgeons' Museum. Cockle was one of the few physicians in his day who also held the RCS Fellowship. His practice at 63 Brook Street was extensive, and he afterwards moved, before his final retirement, to 8 Suffolk Street, Pall Mall, where he practised in the eighties of the nineteenth century. He came up daily to his practice from his country residence at West Molesey, Surrey. Increasing deafness caused him to retire finally about the year 1860, and he lived quietly with his daughter at Molesey till his death on November 14th, 1900. At the time of his death Cockle was Consulting Physician to the Royal Free Hospital and Examining Physician to the Royal National Hospital for Consumption, and had been Hon Physician to the Warehousemen, Clerks and Drapers' Schools. He was President of the Medical Society of London in 1879; a corresponding member of the Society of Science and Medicine, Berlin; corresponding member of the Philosophical Society of Queensland; a Fellow of the Society of Antiquaries and of the Linnean Society. Publications: *An Essay on the Poison of the Cobra di Capello*, 8vo, London, 1852. Translation of Georg Weber's *Clinical Handbook of Auscultation and Percussion*, 8vo, London, 1854. *Lectures upon the Historic Literature of the Pathology of the Heart and Great Vessels*, Part I: From the earliest authentic records to the close of the Arabian epoch, 12mo, London, 1860. *On Insufficiency of the Aortic Valves in Connection with Sudden Death*: with notes historical and critical, 8vo, London, 1861; 2nd ed., 1880. *On Intrathoracic Cancer*: Part I, Introductory, and Historic Sketch; Part II, Contributions to the Pathology of the Disease, 8vo, London, 1865. *Thoughts on the Present Theories of the Algide Stage of Cholera*, 8vo, London, 1866. *The Oration on the Occasion of the Centenary of the Medical Society of London, being a Review of some recent Doctrines concerning the Mind*, 8vo, London, 1874. *Contributions to Cardiac Pathology*, 12mo, London, 1880. "The Influence of the Discharges and Nervous Shock on the Collapse of Cholera," 12mo, London, 1867; reprinted from *Med. Press and Circular*. "On Clinical Method." Introductory Address at the Royal Free Hospital, London, 1877. *Notes on the Surgical Treatment of Aortic Aneurysm*, being in part a reprint of some papers in the *Lancet* on the same subject, published in the years 1869 and 1872, 8vo, London, 1877. "Past and Present Phases of Physic." Introductory Address at the Grosvenor Place School of Medicine, London, 1859. "On Spontaneous Gangrene connected with Disease of the Heart and Great Vessels." - *Med. Mirror*, 1864, i, 821, 400. "On Mammary Abscess during Lactation." - *Med. Circular*, 1853, iii, 91.