The Trotter family has long been settled in Gloucestershire, where it had an honoured connexion with the Baptist Church. Wilfred Trotter was born in London on 3 November 1872, the son of Howard Birt Trotter of Coleford, Gloucestershire, and Frances Lewes, his wife. His early years were spent at Coleford, where he suffered from disease of the spine, for the cure of which he was ordered prolonged rest. He was afterwards a pupil at Bell's Grammar School, Coleford, and at Gloucester. His father, who retired first to Park Avenue, Willesden Green, London and later to Aberystwyth, sent his son to University College School, where he remained from 1888 to 1890. Having gained the first entrance exhibition Wilfred Trotter entered the Medical Faculty of University College in October 1891. He was awarded the gold medal and the University scholarship at the BS examination in 1896, and was placed in the honours list in medicine at the University of London in the following year. At University College Hospital he was house surgeon to Arthur E J Barker from April to September 1897, and house physician to Charlton Bastian, FRS from October 1897 to March 1898. He was surgical registrar 1901-04; assistant demonstrator of anatomy in the medical school 1904-06, when G D Thane was the professor; assistant surgeon 1914, on the resignation of Victor Horsley; surgeon 1915, on the retirement of Bilton Pollard; Holme lecturer in clinical surgery 1908-38; director of the surgical unit, with the title of professor of surgery, 1935-38, in succession to C C Choyce; and consulting surgeon 1938. He was also a Fellow of University College, London. During his years of waiting for a vacancy on the surgical staff at University College Hospital, he was an assistant surgeon at the East London Hospital for Children at Shadwell. At the Royal College of Surgeons he was a Hunterian professor in 1913, a member of the Council 1924-39, a vice-president 1933-34, and Hunterian orator 1932. He was a member of the Medical Research Council 1929-33, and was elected a Fellow of the Royal Society in 1931, where he was a member of Council 1932-33 and a vice-president 1935-37. He was surgeon in ordinary to King George V. 1928-32, and in that position shared with Sir Hugh Rigby, Serjeant-Surgeon, the responsibility for the surgical treatment of the King through a prolonged illness. He received his patent as Serjeant-Surgeon in 1932, in succession to Rigby, and resigned the office in August 1939, having served King George V, King Edward VIII, and King George VI. In 1932 he was president of the Association of Surgeons, and in 1938 he received the gold medal of the Royal Society of Medicine. He married in 1910 Elizabeth Mary Jones, sister to Ernest Jones, MD, director of the London Clinic of Psycho-Analysts, who had been a fellow student with him at University College. She survived him with a son, W R Trotter, MRCP 1937, DM Oxford. 1942, also of University College Hospital. His health began to give anxiety to his friends in 1935, when he relinquished private practice and devoted himself entirely to work at University College Hospital. He died at Pond End House, Blackmoor, Hants on 25 November 1939. A half-length portrait in oils painted by Herbert Olivier is in the possession of Mrs Trotter. A replica by the artist was presented to the Royal College of Surgeons. It was reproduced in the *British Journal of Surgery*, 1939-40, 27, 625. Trotter had physical and mental qualities unusual in a surgeon who attains a very high position in his profession. He carried through life evidence of illness in childhood. Frail-looking, stooping somewhat, and prematurely old; quiet in manner, reticent, and speaking very softly, it was difficult to believe that he could bear the fatigues and anxieties of a hospital surgeon and teacher coupled with a large private practice. But under his frail aspect and quiet manner was a keen intellect directed towards the philosophical and psychological aspects of medicine, critical judgment, wit, and a rare operative skill. *As the preceding memoir by Sir D'Arcy Power lacked an appreciation of Trotter's scientific work, it has been thought well to add the following paragraphs:* At University College Hospital as a young man Trotter had come under the influence of a group of remarkable scientifically minded surgeons and physicians who opened new horizons for his thought; chief among these he recalled Horsley, Barker, and Bastian (mentioned above) with Sir Thomas Barlow, FRS, and Sir John Rose Bradford, FRS. Promotion in the hospital came slowly to him at first, his academic career having been sound rather than brilliant, and after holding the surgical registrarship 1901-04 he had to fill in two years, in his early thirties, demonstrating anatomy at University College. In the meantime, however, he was developing his own thought, educating himself, as he said half seriously, on the English novelists, particularly Jane Austen and Henry James; while through Ernest Jones, who was shortly to become his brother-in-law, he had learnt of the new schools of psychology stemming from Vienna and Zurich under the impetus of Sigmund Freud's revolutionary teaching, which was slowly making its way to recognition. Trotter worked out, during the lean year 1905, an analysis of the herd instinct in man. He showed that the conditions of life of gregarious animals gave rise to an instinct of such power that its workings could be followed through the emotions and even the intellectual processes behind man's social behaviour. Karl Pearson, also of University College, had shown that man's instinct to sacrifice his individual interests for the sake of his fellows arose directly from this instinct of the herd; but Trotter went more deeply into the human rationalization of this urge, at a time when it had been hardly explored. The essay was published in two parts in the *Sociological Review* in 1908 and 1909, and attracted the attention of psychologists (see Bibliography below, No 7). It was re-issued in 1916 as the beginning of a much larger book (No 30), in which he applied his analysis to the nations then at war. This later part was too strongly coloured by Trotter's own patriotism, but made a popular appeal in its comparison of English social life to that of the bee, a forced analogy, and German life to the herd movements of the predatory wolf. The book was revived at the beginning of the second German war in 1940, and at that time Trotter wrote a remarkable letter (No 71) to *The Times*, 26 September 1939, briefly summarizing his analysis of these psychological traits in democracy and autocracy. It has been re-issued with a biographical introduction in 1953. After this speculative excursion, Trotter next applied himself to the physio-psychological problem of pain. Head and Rivers in 1905 had made self-experiments on the regeneration of the peripheral sensory nerves of the skin, concluding that these nerves had evolved from two components, the protopathic and the epicritic nerves: the former registering gross sensations and pain, the latter touch, localization and temperature. (The afferent nervous system from a new aspect, by H Head, W H R Rivers, and J Sherren. *Brain*, 1905, 28, 99.) Trotter was sceptical of these deductions, and with H Morriston Davies, FRCS he repeated and elaborated the research. Using each other as controls, which he considered were lacking from the Head-Rivers experiments, Trotter and Davies cut different skin nerves in seven experiments. Their detailed observations were published in 1907 and subsequent years (Nos 3, 6, 22), including in 1913 a critique of the Head-Rivers hypothesis, for Trotter could not accept the theory of dual origin. He came to believe that the regenerated nerve must be looked on as abnormal and pathologic, not a pure regrowth of the original, and he attributed its hypersensitivity to lack of insulation from other tissues. He developed this idea in later studies (Nos 45, 50, 53), though he never again found opportunity to pursue it in the laboratory. In these early years before the first world war, Trotter was carrying on experimental work at University College Hospital at the same time as his surgical practice, when science and surgery were more usually separate. He also inspired his colleagues and pupils to similar work; and it was thus no surprise to those who knew him best when in his last years he abandoned his large private practice and restricted himself to scientific work based on his hospital clinic. But the middle years of his life were more and more occupied with pure surgery, as his brilliant technique and deep knowledge led him to explore some of the more difficult fields and brought him the time-consuming reward of being very generally accepted as the surgeon's surgeon. From the surgery of the central nervous system (Nos 1, 4, 23, 27) and the thyroid gland (Nos 5 and 13), which his master Horsley had practised before him, he turned to the intricate problems of larynx and pharynx surgery, elaborating a new anatomical approach for dealing with malignant disease of these organs (Nos 10 and 15). This work was first fully described in his Hunterian lectures (No 21), and definitively in several later papers (Nos 49, 55, 59, 60 and 70). Trotter's craftsmanship as a surgeon was of a very high order, based on a sound knowledge of anatomy. One observer said that "a pharyngeal growth would present itself to him in the middle of his incision apparently of its own volition"; another that "it was a perfect joy to watch him remove a simple appendix, the knife handled as Vermeer must have wielded his brush, the needle with the skill of an embroidress, and, above all, the surpassing gentleness of his manipulation". In his later years he played a full part in the corporate life of surgeons and scientists, as a valued member of the Councils of the Royal College of Surgeons and the Royal Society. He also became more widely known through a series of philosophic addresses on the background of medical and social life. In 1923 he read the opening paper to the section of surgery at the British Medical Association's annual meeting at Portsmouth (No 40), and in 1924 gave the annual oration to the Medical Society of London (No 44). In his Hunterian oration (No 64) he took as his theme "The commemoration of great men", and tried to show that it would be better to help great men during their lives than commemorate them when they were dead. (See also Nos 56, 58, 65, 68, 69.) He had long recuperated himself from the strains of surgical practice by escape to the quiet of the country, at first to a cottage in Sussex and, after his marriage, to a house in Hampshire, where he cultivated his garden with the meticulous search for perfection that he gave to his surgery and his Socratic philosophizing. His criticism was keen, and though it was often destructive it gave food for thought which led to valuable results. His wit was swift and biting, as when he once said to an assistant in the operating theatre "Mr Anaesthetist, if the patient can keep awake, surely you can". His extreme simplicity and modesty seemed affected to some observers, but was more probably due to that sardonic tone of mind which saw no value in any human activity except the lifelong perfecting of skill, dexterity, and judgement. Publications: Trotter published 71 papers; a bibliography was drawn up in the RCS library and published with modifications in the Royal Society's obituary notice (see below). The papers mentioned above are listed here with their numbers from the full bibliography. A paper on "Panic and its consequences" appeared posthumously in *Brit med J* 1940, 1, 270. His son, Dr W R Trotter; edited a selection of his articles as *Collected Papers* for the Oxford University Press, 1941. 1. Cheyne-Stokes phenomenon in acute cerebral compression. *Lancet*, 1906, 1, 1380. 3. The exact determination of areas of altered sensibility, with H M Davies. *Rev Neur Psych* 1907, 5, 761. 4. Commoner symptoms of cerebellar abscess. *Brit med J* 1908, 1, 612. 6. Experimental studies in the innervation of the skin, with Davies. *J Physiol* 1909, 38, 134. 7. The herd instinct. *Sociol Rev* 1908, 1, 227; 1909, 2, 36. 10. Continuous fibroma of neck and larynx, or malignant disease of the larynx with enlargements of glands in the neck. *Proc Roy Soc Med* 1908-09, 2, laryng pp 82-87 (5 February 1909). This paper follows up Sir Felix Semon's article on the same case in the same volume, pp 8-10 (6 November 1908). 15. Clinically obscure malignant tumours of the naso-pharyngeal wall. *Brit med J* 1911, 2, 1057. 21. The principles and technique of the operative treatment of malignant disease of the mouth and pharynx, Hunterian lectures, RCS, 3 and 5 March 1913. *Lancet*, 1913, 1, 1075. 22. The peculiarities of sensibility founds (sic) in cutaneous areas supplied by regenerating nerves, with Davies. *J Psychol Neurol*, Leipzig, 1913, 20, Ergänzungsheft, 2, 102-150, with German summary of paper read at Congress of International Society for medical Psychology and Psychotherapy. 23. Chronic subdural haemorrhage of traumatic origin and its relation to pachymeningitis haemorrhagica interna. *Brit J Surg* 1914-15, 2, 271 (October 1914). 27. The principles of operative treatment of traumatic cerebral lesions. *Brit J Surg* 1914-15, 2, 520-543 (April 1915). 30. *Instincts of the herd in peace and war*. London, Unwin; New York, Macmillan. February 1916, 213 pp. Second edition with postscript, 1919; 11th impression, 1930; 12th impression, London, Benn, February 1940, 264 pp; new edition, Oxford University Press, 1953. 40. Anaesthetics from the surgeon's point of view. *Brit med J* 1923, 2, 791. 44. Certain minor injuries of the brain. *Trans Med Soc Lond* 1924, 47, 270. 45. Sensibility of the skin in relation to neurological theory. *Lancet*, 1924, 1, 1252. 49. The surgery of malignant disease of the pharynx. *Brit med J* 1926, 1, 269. 50. The insulation of the nervous system. *Brit med J* 1926, 2, 103. 53. The interpretation of pain. *Camb Univ Med Soc Mag* 1927-28, 5, 114. 55. Operations for malignant disease of the pharynx. *Brit J Surg* 1928-29, 16, 485. 56. The functions of the human skull. *Nature*, 1929, 123, 522. 58. Observation and experiment and their use in medical sciences. *Brit med J* 1930, 2, 129. 59. Some principles in the surgery of the pharynx. *Lancet*, 1931, 2, 833. 60. Malignant disease of the hypopharynx and its treatment by excision. *Proc Roy Soc Med* 1931-32, 25, 431. 64. The commemoration of great men, Hunterian oration, RCS, 15 February 1932. *Brit med J* 1932, 1, 317; *Lancet*, 1932, 1, 381. 65. De minimis. *Lancet*, 1933, 1, 287. 68. General ideas in medicine, Lloyd Roberts lecture, 30 September 1935. *Brit med J* 1935, 2, 609. 69. Has the intellect a function? *Lancet*, 1939, 1, 1419. 70. Malignant disease of the pharynx: a problem in practical medicine, in T R Hill *Treatment of some common disease*, Edinburgh, Livingstone, 1939, pp. 164-184. 71. The mind in war, democracy's chief advantage. *The Times*, 26 September 1939, p 4c, reprinted in *Royal Society, Notes and Records*, 1939, 2, 173.