In 1944 he accepted a commission to edit the medical series volumes of the Official History of Australia in the War of 1939–1945 but he was killed in a plane crash in March 1945, before he could begin the work.

[1] He was the youngest of fifteen children of Colonel Major Francis Downes—a British Army officer—and his wife Helen Maria, née Chamberlin, only five of whom survived to adulthood.

[2] After service in the Crimean War,[3] Colonel Francis Downes served as commandant of the Colonial forces of South Australia and Victoria and retired with the rank of major general in the Australian Army in 1902.

In March 1901, at the age of 16, he joined the Victorian Horse Artillery (St Kilda Battery), a part-time volunteer militia unit, as a trumpeter.

In May 1901 he served in this capacity at the opening of the inaugural Parliament of Australia by The Duke of Cornwall and York at the Royal Exhibition Building.

[10] He served his residency at Melbourne Hospital and became a general practitioner in Malvern, Victoria, but soon returned to the university to pursue a doctorate.

His Doctor of Medicine (MD) thesis, entitled "The anatomical relations of the thymus, especially considered in regard to thymic death with an account of cases of abnormality", was accepted in 1911.

[1] After training at the Broadmeadows Army Camp near Melbourne, the unit embarked for Egypt on the transport SS Chilka on 2 February 1915.

[19] After the evacuation of Gallipoli, Downes was appointed Assistant Director of Medical Services (ADMS) of the newly formed Anzac Mounted Division on 15 March 1916.

[22] A poorly organised casualty evacuation effort caused preventable hardship and suffering for the wounded, and resulted in several avoidable deaths.

[24] The Commander in Chief of the Egyptian Expeditionary Force (EEF), General Sir Archibald Murray, declined to assign blame to any individual, but implemented the inquiry's recommendations for improving the casualty evacuation process.

To combat these, Downes obtained the services of Lieutenant Colonel Charles James Martin,[25] and created the Anzac Field Laboratory to investigate these diseases.

He in turn converted Downes to the belief that "provided water is available in adequate amount the heat mechanism of the body can defy all ordinary climatic ranges of temperature even under conditions of hard work.

By June, Rupert was becoming increasingly immersed in preparations for the Third Battle of Gaza and Doris, who had become pregnant during her visit, decided to return home.

[19] On her return journey to Australia in June 1917, her ship, the P&O liner RMS Mongolia struck a mine and sank in the Indian Ocean with the loss of 23 lives.

[32][33] On 10 August 1917, Downes became Deputy Director of Medical Services (DDMS) of the Desert Mounted Corps, while still retaining the post of ADMS AIF Egypt.

[35] In the Jordan valley in 1918, Downes was confronted with an epidemic of malaria and vigorous preventative and prophylactic efforts were required to bring it under control.

The task was made more difficult by the poor communications and transport shortages, which hampered the delivery of supplies and evacuation of the hospitals; by shortages of medical units; and by the actions of Lieutenant Colonel T. E. Lawrence, who was more concerned with establishing the political authority of Hussein bin Ali, Sharif of Mecca over Damascus.

[37] At this point the Desert Mounted Corps itself began to experience epidemic diseases, particularly of bronchopneumonia, cholera and malaria, putting the medical services under great strain.

Through extraordinary measures, including the diversion of lighthorsemen and motor vehicles to medical units, Downes managed to evacuate the sick to Beirut, and the crisis abated.

In a 1922 paper published in the Medical Journal of Australia, he examined 100 cases of tonsillectomy in children, and concluded that the majority of them were unnecessary.

Despite the best efforts of two eminent medical practitioners, Keith Fairley and Reginald Webster, John succumbed to toxaemia and died in 1933, at the age of 10.

The failure of modern medicine to save his son affected Downes deeply, and led him to abandon his medical career in favour of a military one.

[59] The 1938 Munich Crisis caused people to believe that another war was imminent, and an Army-wide recruiting campaign led by Major General Sir Thomas Blamey doubled the size of the Army from 35,000 in 1938 to 70,000 in 1939.

Still in London, he took steps to obtain the services as consultants of two eminent Australian doctors: the surgeon Sir Thomas Dunhill and Neil Hamilton Fairley, an expert on tropical diseases.

[64] The outbreak of the Second World War caused Downes to curtail the North American leg of his tour and return to Australia in October 1939.

[69] On 5 March 1945, the RAAF Lockheed Hudson aircraft they were travelling in crashed into the sea about 400 yards (370 m) off Machans Beach, just north of the mouth of the Barron River near Cairns in Queensland.

[69] Gavin Long, the editor in chief of the Official History of Australia in the War of 1939–1945, prevailed on Allan S. Walker to write the medical series volumes.

Walker discarded Downes's plans to have specialists write different sections, and ultimately wrote three volumes himself, starting with Clinical Problems of War (1952).

He was working on the fourth and final volume, on the Medical Services of the RAN and RAAF, when he was compelled to quit in November 1956 due to ill-health, and he died in January 1958.