The principal contributions of Sir Thomas Lewis, who was born in Cardiff, were in cardiology and electrocardiography. He also performed research on blood vessels and pain. His observation on the sequence of events that followed stroking sensitive or normal skin with a blunt instrument, known as the “triple response”, was described by Lewis in 1924, and was attributed to the release of histamine-like substance. This response is of interest to neurologists, because intrademal histamine produces a triple response (vasodilatation, weal formation, and flare) in pre-ganglionic, but not post-ganglionic brachial plexus lesions.

Lewis was honoured on a stamp produced by Mauritius in 1981, (Stanley Gibbons no. 624, and Scott no.529) on the centenary of his birth. He is shown here with an electrocardiogram.