Born at Bristol 19 February 1875, the ninth child and sixth son of the Rev John Mackie, Rector of Fylton, Glos, and Annis Bennett his second wife. John Mackie was twice married; there were five sons and two daughters of the first marriage, and one daughter and three sons of the second. He was educated at Dean Close School, Cheltenham, at Bristol Medical School, and at St Bartholomew's Hospital. After winning a surgical scholarship and the gold medal in medicine at Netley, where he worked under Sir Almroth Wright, he passed first into the Indian Medical Service, being gazetted lieutenant on 1 September 1902. During his first year in the east Mackie served as medical officer to the famous mission undertaken by Sir Francis Younghusband, KCSI, into Tibet. He was promoted captain on 1 September 1905, and appointed assistant director of the Plague Research Laboratory at Parel, Bombay. Plague had appeared in Bombay in 1896 and spread east and north, and the Plague Research Laboratory had newly been established, when Mackie joined its staff, under the Bacteriological (later Medical Research) Department of the Government of India. The British Plague Commission under (Sir) Charles James Martin, CMG, arrived in India in 1905 and made its headquarters at Parel. Here Mackie began the good work on plague to which he returned some twenty years later, but his first original discovery was of the part played by the body-louse in transmitting the spirillum of relapsing fever (1907). This discovery led to C J H Nicolle's (1866-1936) incrimination of the louse in typhus (1910). From September 1908 to November 1909 by request of the Government of India he was attached to the Royal Society's third Sleeping Sickness Commission under Sir David Bruce, FRS (1855-1931), in Uganda, and contributed largely to its reports, working on the development and transmission of the trypanosomes in collaboration with Bruce, Lady Bruce, and Albert Ernest Hamerton, CMG DSO, of the RAMC. The Government of India had feared the possibility of the trypanosome being conveyed to India in the blood of infected Indians and spread by Indian flies, or even that the tsetse fly itself might be imported. While in Uganda Mackie was able to enjoy his love of sport. Returning to India he served in 1910-11 as special government research officer on kala-azar in Assam. The causal organism, the Leishman-Donovan parasite, had been discovered in 1903 (*Brit med J* 1903, 1, 1252; 2, -79) but its mode of transmission was unknown; Mackie identified the sandfly as responsible, a finding authenticated fourteen years later by the Calcutta School of Tropical Medicine's team and the Government of India's special kala-azar commission. During the war of 1914-18 he served in Baluchistan, Persia, Mesopotamia, and France, having been promoted major, IMS, on 1 March 1914. He speedily and efficiently established a central bacteriological laboratory in Mesopotamia in 1916, after the breakdown of the original medical organization there. The strain of cholera vibrio which Mackie isolated from a colleague was maintained as type of the organism endemic there. He was created OBE for his services on 3 June 1918, and was twice mentioned in despatches (*London Gazette*, 27 August 1918, 21 February 1919). In 1919 he was elected an FRCP. In 1920 Mackie was appointed professor of pathology at Calcutta University, but was transferred in 1921 to be director of the Pasteur Institute at Shillong in Assam. He was promoted lieutenant-colonel on 1 March 1922. In 1923 he returned as director to the Haffkine Institute for Medical Research in Bombay, where his own best work had been begun. He held the appointment until 1932, when he retired from the IMS. His chief researches were on schistosomiasis and sprue, in collaboration with N Hamilton Fairley, CBE FRS, and others. In 1928-32 he was officiating public health commissioner with the Government of India; and in 1928-31 served as chairman of the League of Nations expert committee on plague. He represented the Government of India at the Office internationale d'Hygiene publique in Paris in 1919, 1922, 1926 and 1930. In 1925 he was president of the medical and veterinary section of the Indian Science Congress and in 1932 president of the tropical diseases section at the BMA centenary meeting in London. He was an Honorary Surgeon to King George V. He served as Surgeon General in the Government of Bombay in 1929, and was placed on the select list for promotion in the IMS on 3 April in that year. In 1931 he was once more acting director of the Pasteur Institute at Shillong. He was created CSI on 3 June 1932, when he retired. On his return to England Mackie became a lecturer at the London School of Hygiene and Tropical Medicine, and served as pathologist (1933-37) at the Tropical Diseases Hospital, London; he lived at Felden, Herts. He was then appointed chief medical officer of the British Overseas Airways Corporation, and made many arduous journeys by air to tropical colonies in Africa and Asia, supervising the sanitary requirements of the chain of aerodromes which was being established. He was particularly interested in the prevention of yellow fever on African aerodromes, and the fumigation of aircraft against bloodsucking and disease-carrying insects. He delighted to view from the air the great herds of game in central Africa, such as he had seen only from the ground twenty years earlier in Uganda. Mackie lived during this period in his native Bristol at 3 Golding Avenue, and later at Pack Horse Farm, Mark, near Highbridge, Somerset. During the height of the air-raids on Bristol in 1940-41 he was an active warden and first-aid rescue worker in the streets; his wife also served as a warden. Mackie married twice: (1) in 1913 Gladys May, daughter of W J Ball; their only child, Laurence Percival, was in 1944 a medical student serving as lieutenant, RNVR; and (2) in 1926 Mary Elizabeth H Elwes, a widow, daughter of W Haddon Owen of Louth, Lincs, who survived him with two sons. He died in a nursing home at Clifton on 15 July 1944. Mackie was one of the most distinguished medical scientists who have served in India, and after retirement from the Indian Medical Service his abilities were in demand at home. His work on plague, relapsing fever, sleeping sickness, kala-azar, enteric dysentery, cholera, schistosomiasis, hydrophobia, and sprue was original and of first rate quality; but his administrative gifts and their contribution to tropical hygiene were of almost higher value. He was a good speaker in debate and council, and a man of gaiety and wit, who enjoyed life to the full, while a most busy and productive worker. Mackie was a corresponding member of the American Society of Tropical Medicine and of the Société de Pathologie exotique at Paris. There is a photograph of him in the College collection, presented by Mrs Mackie, in white coat at his microscope. Select bibliography:- The part played by *Pediculus corporis* in the transmission of relapsing fever. *Brit med J* 1907, 2, 1706. The development of *Trypanosoma gambiense* in *Glossina palpates*. *Proc Roy Soc B* 1909, 81, 405. Sleeping sickness in Uganda: duration of the infectivity of the *Glossina palpates* after the removal of the lake-shore population. *Proc Roy Soc B* 1910, 82, 56. The development of trypanosomes in Tsetse flies. *Ibid* p 368. Experiments to ascertain if cattle may act as a reservoir of the virus of sleeping sickness (*Trypanosoma gambiense*). *Ibid* p 480. Experiments to ascertain if *Trypanosoma gambiense* during its development within *Glossina palpates* is infective. *Proc Roy Soc B* 1911, 83, 345. The progress of kala-azar in a localised community. *Ind J med Res* 1914, 2, 505. The experimental transmission of Indian kala-azar to animals. *Ind J med Res* 1915, 2, 934. Disease in Mesopotamia. *Bristol med-chir J* 1919, 36, 118. Laboratory records from Mesopotamia, with G Trasler: 1. Enteric group. *Ind med Gaz* 1921, 56, 411; 2. Dysentery. *Ibid* March 1922, 57, 85; 3. Cholera.*Ibid* April 1922, 57, 121. The problem of kala-azar. *Ind med Gaz* 1922, 57, 326. Commentary on the foregoing (plague) papers on the production of immunity against plague by vaccine. *Ind J med Res* 1924, 12, 331. The insect menace (Presidential address to.Indian science congress). *Ind med Gaz* 1925, 60, 172. The present position of the plague problem. *Far East Assoc Trop Med Congress 7* Calcutta 1927, *Trans* 2, 2. Progress report on the sprue inquiry, with N H Fairley and others. *Ibid* 1927, 2, 248. Yeasts and sprue, with G D Chitre. *Ind J med Res* 1928, 11, 749. Animal experiments and sprue, with the same. *Ibid* 1928, 16, 49. The association of bowel diseases with Vitamin C deficiency, with G D Chitre. *Ibid* 1928, 16, 77. The morbid anatomy of sprue, with N H Fairley. *Ibid* 1928, 16, 799. Bacteriology of sprue, with S N Gore and J H Wadia. *Ibid* 1928, 16, 95. The blood in sprue, with N H Fairley and H S Billimoria. *Ibid* 1928, 16, 831. The clinical aspect of sprue, with N H Fairley. *Ibid* 1929, 16, 831. Studies in Schistosoma spindale, parts 1-6, with N H Fairley. *Ind med Res Mem* No 17, September 1930. The serum therapy of plague, with B P B Naidu. *Lancet* 1931, 2, 893. Presidential address, tropical diseases section, British Medical Association, centenary meeting, London, 1932. *Brit med J* 1932, 2, 325. The Jarisch-Herxheimer reaction in trypanosomiasis, with a note on the morular cells of Mott. *Trans Roy Soc trop Med* 1935, 28, 377. The destruction of mosquitoes in aircraft, with H S Crabtree. *Lancet* 1938, 2, 447.