Born at Sheffield, 15 January 1885, the eldest son and first child of the Rev James Todd, Wesleyan minister, and Katherine Wingate, his wife. He was educated privately and afterwards went to school at Nottingham. He then entered the Victoria University, Manchester, where he won the University scholarship at the intermediate MB examination and graduated MB BCh with first-class honours in 1907, and took a postgraduate course at the London Hospital. He lectured on anatomy in the University when A H Young was professor and subsequently under Professor Elliot Grafton Smith, who appreciated his merit and incited him to do some good original anatomical research. In 1910 he was elected the Tom Jones surgical research scholar, and became interested in the anatomical teaching of dental students. He left England on 30 November 1912 to take up an appointment as professor of anatomy in the Western Reserve University, Cleveland, Ohio, and here he spent the rest of his life. During his later years he acted as director of the Brush Foundation at Cleveland, which was founded in 1928 by Charles Francis Brush to study "the restriction of population and the betterment of the human race, more especially in connexion with heredity and environment." He married Eleanor Pearson of Manchester on 9 November 1912. She survived him with two sons and a daughter. He died at his house, 2687 Shaker Road, Cleveland Heights, on 29 December 1938 suddenly, with a coronary thrombosis. During the first world war he held a commission as captain in the Royal Canadian Army Medical Corps, as he retained his British nationality. Todd in the United States and Herbert Henry Woollard in England did much to revolutionize the outlook of anatomy. Todd, by his paper on the "Arterial lesion in cases of cervical rib", published in 1913 in the *Journal of Anatomy*, 47, 250, was amongst the first to call attention to the arterial changes which follow pressure on the sympathetic nerve supply of the vessel. Perhaps his greatest contribution was his demonstration that from infancy to old age the human skeleton undergoes a succession of changes, and by recognition of these changes that it is possible to assess the approximate age of any given skeleton. By 1933 he had examined 3,407 human skeletons, all with well-ascertained racial and social histories. Another field of enquiry was the mobility of the alimentary canal, and especially disturbances in rhythm and vigour produced by mental states. The results were summarized in 1930, when he delivered the Beaumont lectures, and they were published under the title *The behaviour patterns of the alimentary tract* in the same year. Through the Brush Foundation he organized a systematic and continued examination of 800 children, to investigate the growth changes. The results appeared in the *Atlas of skeletal maturation*, with 75 plates, London, 1937. It gives standard examples of the stages in ossification which the hand passes through from birth to maturity, and is labelled "Part I". Another field of work was the growth of the face and its bearing on the practice of the dental surgeon. It was said of Todd that he was quite tireless, working with an evangelical fervour, his mind so teeming with ideas that it early appeared a single life would be too short to enable him to encompass all he wished to do. He had a keen sense of humour, was easy to work with, and had many interests outside his anthropological work.