Major William Heaton Horrocks was educated at Owens College Manchester where he matriculated at the age of 15 years and took his BSc. He graduated in medicine in London in 1883. For a time he was resident at the Brompton Hospital for Chest Diseases and then went to the Guildford Hospital.
5 Feb 1887 Commissioned Surgeon-Captain on passing out of Netley.
1895 While in India, he married Minna, daughter of the Rev J C Moore, of Connor, County Antrim. He had a son, Brian Gwynne, and a daughter, Jean Moore. His wife died in 1921.
1897–1903 Returned from India to take appointment of Assistant Professor of Military Hygiene at the Army Medical School Royal Victoria Hospital Netley, and afterwards at the Royal Army Medical College Millbank.
5 Feb 1899 Promoted Major RAMC.
1903–1909 Sanitary Officer at Gibraltar.
1904–1906 Member of the Army Medical Advisor Board as an expert on sanitation.
1904 Member of the Royal Society's Commission on Mediterranean Fever. The other members of the Mediterranean Fever Commission were: Staff–Surgeon Ernest Shaw RN, Dr Themistocles Zammit, Dr Ralph Johnstone, Captain James Crawford Kennedy RAMC, and Staff-Surgeon Ernest Gilmour RN.
Malta 1904 Appointed member of the subcommittee of the Tropical Diseases Committee of the Royal Society, which was set up in Feb 1904 to investigate Mediterranean Fever. The members of the Commission working under their Chairman Colonel Sir David Bruce, were: Maj Horrocks, Capt Crawford Kennedy, Dr Themi Zammit, Staff Captain E A ShawRN, and others detailed from time to time.
Sept 1904 Returned to England.
Malta May 1905 Arrived from Gibraltar as part of the Mediterranean Fever Commission.
23 June 1905 Maj Horrocks reported the discovery of the Micrococcus melitensis in the milk of an apparently healthy goat. By 26 June, he had found the microbe in the milk of 5 goats whilst Dr Themi Zammit had found it in the blood of one of three goats on 18 June 1905. Sir David Bruce had previously proved that the cause of this fever was a microbe, Micrococcus melitensis, but it was Horrocks who discovered that the disease was transmitted by goat's milk.
On 18 July 1905, Col David Bruce received preliminary reports from Maj Horrocks, Capt Kennedy and Dr T Zammit on the propagation of Malta Fever by means of goats. As many as 41% of the goats in Malta were infected and 10% of the goats supplying milk to the various parts of Malta were excreting the Micrococcus melitensis in their milk.
Malta 1906 Member of the Mediterranean Fever Commission.
July 1908 Editor Journal of the Royal Army Medical Corps. Edited the journal continuously for 32 years.
In 1908, Horrocks demonstrated the passage of anthrax bacilli into the milk of a cow dying of the disease.
19 May 1911 Lieutenant Colonel RAMC.
20 May 1911 Brevet Colonel L/RAMC.
1914 Appointed King's Honorary Surgeon. Member of the Army Medical Advisory Board, and Chairman of the Anti–Gas Committee to devise methods for counteracting the use by the enemy of poison gases.
In his capacity of Member of the Army Sanitary Committee, he was instrumental in sending out to the armies in France and Belgium, Mobile Water Sterilizers, the Mobile Hygiene Laboratories, in the supervising and altering the Water Carts, and in the issue of the Test Case for Water Supplies, known as the Horrocks Box.
22 Jan 1915 Awarded the Chadwick Gold Medal of the Royal Society of Arts for his distinguished work in promoting the health of the army.
1 Mar 1915 Colonel L/RAMC.
1919 Appointed the first Director of Hygiene at the War Office.
- Entry No: 7220. Johnston W. Roll of Commissioned Officers in the Medical Service of the British Army. Vol 1 (20 June 1727-23 June 1898. Aberdeen (1917).
- Distribution of RAMC Officers. Corps News Vol IV June 1905 No 6.
- Colonel Sir William Heaton Horrocks, KCMG, CB. J R Army Med Corps 1953, ;99(4):137-40 (July 1953).
- Rizzo Naudi J, 2005. Brucellosis The Malta Experience A celebration 1905-2005, Enterprises Group, Malta, pp 59, 69.
- Horrocks W H, Reports of the commission appointed by the Admiralty, the War Office and the Civil Government of Malta for the investigation of Mediterranean Fever under the supervision of an advisory committee of the Royal Society.
- Obituary Br Med J (1941), 1; 4180: 220 (Published 8 February 1941).
- Obituary Br Med J (1941), 1; 4180: 258 (Published 15 February 1941).
- The late Colonel Sir William Heaton Horrocks J R Army Med Corps, LXXVI: 1; 3 (Published January 1941).