[1] The four years which he spent at Bart's were important, and marked by his studies on iron-deficiency anaemia, on the treatment of haematemesis, and on the dangers of ritual purgation, a contribution which deserves to be ranked with Richard Asher’s later questioning of the value of arbitrary periods of rest in bed.

The development of radioactive isotopes, coupled with the construction of the Oxford Shadow Shield total body counter in the Nuffield department of medicine, enabled many studies to be made on the absorption of iron and vitamin B12.

[1]In 1937 he was a co-founder of the British Society of Gastroenterology along with Arthur Frederick Hurst, John Ryle, Henry Letheby Tidy, and Lionel Hardy.

[6] Witts wrote about his opinions on medicine as ‘Doctor Don’ in 1939 in The Lancet and, years later, in the ‘Personal Views’ series in the British Medical Journal.

[4] Under the auspices of the Royal College of Physicians, he delivered in 1961 the Lumleian Lectures on Some aspects of the pathology of anaemia and in 1971 the Harveian Oration on The medical professorial unit.