OBITUARY : Dr Daniel Cunningham

Daniel Cunningham was interested primarily in the control of human breathing, with its ramifications into exercise, body temperature, asphyxia, anaesthesia, disease, mining, diving, aviation and mountaineering, and it is a tribute to his distinction that not only the first four-minute miler, (Sir) Roger Bannister, but also the first conqueror of Everest, (Sir) Edmund Hillary, should have trodden the rolling rubber floor in the Oxford University Laboratory of Physiology.

Daniel Cunningham was born in Kausali, India in 1919, the son of Dr John Cunningham, IMS, Director of the Pasteur Institute, Madras, whose brothers were Admiral of the Fleet Lord Cunningham and General Sir Alan Cunningham. Dan, after nine years at Loretto, won a Nuffield Medical Exhibition to Worcester College, Oxford. In passing the First examinations for the Oxford BM BCh he won the Theodore Williams Scholarships in Physiology and Anatomy, the subject in which his grandfather had achieved world-wide fame. He went to Edinburgh for his clinical course, and there, with his distinguished contemporaries Gus Born and D.H. Clark, persuaded the authorities to accept their newly condensed syllabus, which allowed them to qualify six months earlier than normal, and so enter the forces early.

He had an adventurous war in the RAMC and the 3rd Parachute Brigade, with whom he served from Normandy to the Baltic and landed at Arnhem. In September l945 Dr H.M. Sinclair was looking for doctors to lead his nutritional survey teams in Germany, and, remembering Cunningham's spectacular performance at Oxford, got him seconded as Major, RAMC, to lead the headquarters team in Dusseldorf.

By dint of his tact and intelligence, Cunningham made a great success of this, but administrative problems outside his control prevented completion of his work on the normal plasma protein concentrations in subjects suffering from hunger oedema and nocturia.

Back at Oxford, he got First Class Honours in Physiology in 1947 with Geoffrey Dawes as his tutor, and then succeeded to the Radcliffe Medical Fellowship of University College, of which he became an Emeritus Fellow. He proved to be a devoted tutor, and when appointed, after holding the Schorstein Research Fellowship, to a Lecturership in the University Laboratory of Physiology, a productive and co-operative research scientist.

His interest in human nutrition naturally brought him towards the respiratory and metabolic side of physiology, of which C.G. Douglas was the leader in the Laboratory. He was the survivor of the important school of human physiology founded by John Scott Haldane, father of the biologist Jack Haldane (JBSH) and the writer Naomi Mitchison, and claimed by Daniel Cunningham as his scientific hero.

Unlike his son, J.S. Haldane had misgivings about representing the phenomena of living organisms by means of equations, but from the first Cunningham nailed his colours to the mast of quantitative numerical physiology on the whole animal, and in his early papers his colleagues C.G. Douglas and Roger Bannister went enthusiastically with him. Bannister was his first guinea-pig in investigating the effects of oxygen on respiration and endurance in treadmill running, another famous Versuchskaninchen (German for guinea-pig) being Jeffrey Archer.

The treadmill constituted one of Cunningham's early successes in getting apparatus for experiments on active human beings working smoothly and productively, and foreshadowed his later successes in investigating human phenomena safely and effectively.

Haldane, Douglas and Priestley had made many of the early observations of the venti- latory effects of carbon dioxide (CO2), and Cunningham's next work after that with Bannister was to challenge the multiple-factor hypothesis of John S. Gray and to reinvestigate the important Danish work of Nielsen and Smith on the effect of CO2 at various oxygen concentrations. He decided with his research pupils Cormack and Gee directly to investigate the effect of oxygen lack at various CO2 concentrations, controlled by a feedback system. The CCG papers indicated that in contrast with the linear relation between CO2 and ventilation (V, measured as litres of air breathed per minute), the relationship between oxygen (O2) and ventilation was hyperbolic. With his colleagues Cunningham eagerly accepted this outline of the V, CO2, O2 as the framework for investigating a range of factors affecting V.

These included body temperature, noradrenaline, and blood acidity increased by swallowing ammonium chloride, the electrolyte of the humble Leclanche or "dry" cell, or decreased by the ingestion of baking soda. JBSH was typically one of the first to ingest ammonium chloride, and found that it aggravated his already somewhat inflammable disposition. One of Cunningham's guinea-pigs exhibited the opposite effect, no doubt attributable to his calm conduct of the exhausting four-hour experimental sessions.

Cunningham thus demonstrated that the extremely powerful technique, easily and pro- ductively used in the physical sciences, of separation of factors, was applicable to the more complicated field of human biology. Having shown its value in steady-state situations, he spent the latter part of his career in respiratory physiology investigating transient and oscillatory stimuli, and as a reviewer and lecturer.

In his college as Senior Fellow he played an important part in the election of new Masters. His success in his chosen career was due to his qualities as a human being: modesty, great general ability and determination, an analytical intellect of high quality capable of holding many disparate and complex ideas together, as shown particularly in his lecturing, and great courtesy, humour, integrity and honesty.

He was fortunate in having a remarkable wife, Judith Hill, a professional violinist. Their son is a consultant nephrologist, and their daughter an art historian, expert in English churches.

Brian B. Lloyd

Daniel John Chapman Cunningham, physiologist: born Kausali, India 21 October 1919; Radcliffe Medical Fellow, University College, Oxford 1947- 96; married 1947 Judith Hill (one son, one daughter); died Oxford 26 February 1996.