SUMMARY The theory and application of the quantitative ballistocardiograph is described using the method of Klensch. It is possible to use this method for determining the stroke volume of the heart during anaesthesia simply and rapidly without affecting the circulation. Evidence was obtained showing that halothane may cause direct myocardial depression in some patients. Despite reduction in circulatory resistance a reduction in beart output was observed more frequently than expected. It was demonstrated also that the behaviour of the peripheral circulatory resistance is an important factor in determining stroke volume and results of measurements under the effect of different anaesthetics, ganglionic blockers and vasoconstrictors are presente
