Robert Alexander McCance was born in the country south of Belfast. His father was a linen merchant and owned linen works near the family home. He went to school at St Bees, Cumbria, and always retained a great affection for his school, becoming a governor in later years. He left school in 1919 and served in the Royal Naval Air Service for two years, flying two-seater aircraft from a platform made of planks of wood laid on the midship gun turrets of the battle cruiser HMS Indomitable. This was a rather dangerous exercise and probably accounted for his dislike of flying in later years.

‘Mac’, as he was known to his friends and colleagues, went up to Cambridge on demobilization. He took Part I of the natural sciences tripos and then Part II of the physiology tripos under Sir Joseph Barcroft, who was always one of his heroes. This was followed by three years in the biochemical department under Sir Frederick Gowland Hopkins [Munk’s Roll, Vol.IV, p.535], where he obtained his PhD. In 1925 he went to King’s College Hospital to complete his medical training. While still a medical student he assisted R D Lawrence [Munk’s Roll, Vol.VI, p.275] in the new diabetic clinic and became interested in diabetes, particularly in one of the complications of diabetic coma, sodium chloride deficiency.

After he qualified in medicine, Mac remained at King’s College Hospital and in the early 1930s was in charge of the new clinical biochemistry laboratory. His retained his interest in sodium chloride and decided to produce it experimentally in himself and study its physiological effects. If all went well he would then ask for volunteers among the medical students so that the experiment could be repeated. In the event, five more experiments were made. The salt deficiency was produced by eating a salt-free diet and sweating under hot lamps for two hours a day, for 10 days. By this time about 30% of the body’s sodium had been removed and there was a fall in the concentration of sodium in the extracellular fluids as well as in their volume. The salt-deficient subjects suffered from cramps and breathlessness as well as anorexia and nausea. Many tests were made on them, including renal function and the effects of overbreathing. This investigation, which is now registered as a classic, was important in several ways. First, it was the keystone of his Goulstonian lectures delivered in 1936, with the title ‘Medical problems in mineral metabolism’. The experimental salt deficiency is described in detail in the third lecture. Second, it was Mac’s first venture into self-experimentation and introduced the principle he adopted: that he would never make an experiment on others that he did not also make on himself. Third, the chance observation of his house physician, Winifred Young [Munk’s Roll, Vol.VI, p.485], that newborn infants, like salt-deficient adults, excreted no chloride in their urine, at once aroused his curiosity. This led to his pioneering work on the renal function of newborn infants and animals and his discovery that by every test he applied this appeared to be less efficient than that of adults. It was not until some years later that he realized the importance of growth in maintaining the stability of the internal environment at this time of life.

While still at King’s, a patient with polycythaemia subra vera provided Mac with another line of research. She was treated with acetyl-phenylhydrazine and her absorption and excretion of iron measured. None of the iron set free from the red cells was excreted. Mac followed this up by having an iron salt injected intravenously into himself and giving it to five colleagues; again there was no increase in iron excretion. This led to his hypothesis that the amount of iron in the body is regulated, not by intestinal excretion as had been taught, but by controlled absorption. This hypothesis has stood the test of time.

In 1938, at the invitation of the regius professor of physic, J A Ryle [Munk’s Roll, Vol.IV, p.595], Mac moved to Cambridge as reader in medicine. In 1945 a personal chair was created for him and he became the first professor of experimental medicine in the UK. This was a title he chose himself and one which the university never liked. Mac was a disciple of Claude Bernard, whose book An introduction to the study of experimental medicine, published in 1865, was a treasured possession and provided many aphorisms for his papers and lectures – which he always quoted in the original French. With regard to the word ‘experiment’, so disliked in some quarters, he himself wrote: ‘Those who set out to advance our knowledge of disease and treatment must sooner or later have recourse to experiment, for in the biological sciences experiment is the only way by which advances can be made.’

It was not only disease which inspired Mac’s research. He was always ready to take advantage of unusual situations and to study the physiological response of healthy people to them. The expected food shortages of the second world war were the stimulus for ‘An experimental study of rationing’ and the introduction of the browner ‘National Loaf’ led to a long series of metabolic balance studies in which he participated to investigate the absorption and excretion of calcium and other nutrients when breads made from flours of different extraction rates formed the main part of the diet. There were very small allowances of milk and cheese. It was shown that phytate in brown flour interfered with calcium absorption and that this could be overcome by adding calcium carbonate to the flour. This led to legislation that chalk should be added to flour used for bread-making and the amount of calcium in flour is still regulated by law today.

After the war, Mac persuaded the MRC to support medical and other scientists to go to Germany to study the effects of undernutrition on the civilian population. A unit was set up in Wuppertal and some of the team were there for three years. Mac’s particular interest was hunger oedema. There were many men suffering from this at that time and he wrote a monumental article on ‘The history, significance and aetiology of hunger oedema’ in the MRC Special Report ‘Studies on undernutrition, Wuppertal 1946-49’. Mac did nothing by halves and if he got interested in a subject he delved into its history, ancient and modern, all from the original literature. His knowledge of the classical languages was a great help. It was the same with bread: he spent a great many hours in libraries in various European countries hunting up references for the book Breads white and brown, their place in thought and social history, Philadelphia, Lippincott, 1956, as well as for his paper on hunger oedema. He was not only interested in hunger oedema; his experiences in Germany led him to think deeply about the whole problem of undernutrition and its converse, overnutrition, their causes and effects. In 1953 his thoughts were set out in his Humphry Rolleston lecture ‘Overnutrition and undernutrition’ and he characteristically began the first lecture by using overnourished and undernourished unicellular organisms to illustrate the basic principles of his subject.

The loss of shipping and of lives during the second world war led the Admiralty to seek Mac’s advice on how to improve survival at sea after shipwreck. He and colleagues made investigations during the 1950’s to discover the best means of saving the lives of shipwrecked persons while they were in the water and after they had managed to scramble aboard lifeboats or life rafts – but might not be rescued for a long time. Cold was the greatest hazard and a new covered life raft was designed in which those inside could huddle and keep warm. It was also shown that survivors, if short of fresh water, should never drink sea water. All the recommendations are now standard practice in the Navy.

Mac’s experimental studies on undernutrition and his investigations on the physiology of the newborn led to another interest; normal and retarded growth. ‘Food, growth and time’ was the title of his Lumleian lectures delivered in 1962 and this interest continued in the two years he spent in Uganda after he retired from Cambridge in 1966. He was asked by the MRC to go there to take charge of the infantile malnutrition research unit in Kampala until a new director could be appointed to replace R F A Dean [Munk’s Roll, Vol.V, p.99], the original director, who had recently died. He enjoyed the experience and opportunities for solving new research problems.

Mac spent his last 25 years in Cambridge. He had several accidents; the first causing a fractured femur which meant that his cycling days were over. He still continued to walk quite long distances but as this became more difficult he spent much of his time reading, writing and enjoying visits from his friends and former colleagues and students. He particularly enjoyed talking with those whose lives and careers had been influenced by their time with him. They, too, enjoyed telling him about their doings and experiences. Little eccentricities he may have had and many stories are told about his habit of eating only one large meal a day, but all who had spent time in his department of experimental medicine regarded him with affection as well as with respect. This was very evident at a symposium organized by the British Nutrition Foundation and held in his honour at the College in June 1993.

Mac married Mary MacGregor in 1922 and they had a son and a daughter. Mary died in 1966. There are seven grandchildren and 12 great-grandchildren.