Electrocardiograph, used by Sir Thomas Lewis at University College Hospital, London, by the Cambridge Instrument Co., Cambridge, England, 1930

An electrocardiograph produces graphical records of the electrical activity in a person’s heart. The records are examined by physicians for irregularities that may be a sign of disease.

Thomas Lewis (1881-1945) was a British physician who contributed to the development of cardiology – the study of the structure and diseases of the heart. Made by the Cambridge Instrument Co., Lewis used the machine during his research on the heart at University College Hospital. Lewis wanted to apply laboratory methods to the patient through the use of the electrocardiograph. This move was opposed by some physicians who felt machines devalued their clinical skills and that medical specialities made it impossible to consider the patient as whole person.