Comroe and his associates in their very instructive and concise book on clinical physiology, entitled The Lung, said: “Tests of pulmonary function have proved of definite value both in diagnosis and in guiding therapy of patients with cardiopulmonary disorders.” I am sure that a larger utilization of these tests before operating on cardiopulmonary patients would give anaesthetists a better knowledge of the limitations and of the specific function that has been impaired and would help in the patient’s pre- and postoperative care as much as in the choice of the anaesthetic.