# Dictionary of National Biography, 1927 supplement/Power, William Henry

​POWER, Sir WILLIAM HENRY (1842–1916), expert in public health, the eldest son of William Henry Power, M.D., of Market Bosworth, by his wife, Charlotte Smart, of Bloors Place, Kent, was born in London 15 December 1842. He came of a medical family, being the fifth representative of the profession in direct succession from father to son. Several of his paternal relatives were distinguished mathematicians, one of whom, John Power (1818–1880), became master of Pembroke College, Cambridge. Power was educated at University College School and St. Bartholomew's Hospital. After obtaining his medical qualifications in 1864, he held for some years the post of resident medical officer to the Victoria Park Hospital for diseases of the chest. In 1871 he commenced his long official career in public health on his appointment to the medical staff of the Local Government Board. During his sixteen years' service as medical inspector, Power carried out an immense amount of original work in connexion with infectious diseases, more particularly smallpox, diphtheria, and scarlet fever. His exposition of the danger to public health from the aggregation of smallpox cases formed the basis of administrative action which resulted in the removal of smallpox hospitals outside the metropolitan area, and in the general adoption of corresponding rules for the separation of these hospitals throughout the country. In 1878 he suggested the possibility of the dissemination of diphtheria by the consumption of milk. Subsequently he demonstrated the operation of the same cause in scarlet fever, discovering, moreover, that cows suffering from a vesicular disease of the teats and udder constituted the actual source of infection. As the outcome of investigations initiated by him into outbreaks of lead-poisoning traced to drinking-water, it was found that the acidity to which the plumbo-solvent action of soft moorland waters is due, is bacterial in origin; and further, that lead-poisoning can be prevented by neutralization of the water.
Power was a pioneer in study of the causes and prevention of infantile mortality; and of the injurious effects of defective environment, such as overcrowding and other conditions incidental to insanitary housing accommodation. He also planned and directed much of the work of the medical department of the Local Government Board, including the auxiliary scientific investigations. Owing, however, to his retiring disposition he was little known outside official circles, and much, if not most, of the work which he inspired or directed was published under the names of his colleagues or of his staff.
In 1900 Power succeeded to the post of principal medical officer to the Board, and four years later the food department was established on his initiative. While medical officer he served as Crown nominee on the general council of medical education, and also on the royal commissions on sewage disposal and on tuberculosis. He was elected F.R.S. in 1895, created C.B. in 1902, and K.C.B. on retirement from office in 1908. He died at East Molesey 28 July 1916. He married in 1876 Charlotte Jane, daughter of Benjamin Charles Godwin. She died in 1882, ​leaving two daughters (Mrs. Mervyn Gordon and Miss Constance Power).
[Proceedings of the Royal Society, vol. xc, B, 1917–1919; personal knowledge.]
S. A. M. C.