The beneficial effect of blood letting in the toxemias of late pregnancy is well recognized, but little or no accurate information is available concerning the method of its action. During the course of investigations on the water concentration and the acid-base balance in a series of patients with various clinical types of toxemia (1), certain observations were made at different times in the sa...

Adults with polycythaemia secondary to cyanotic congenital heart disease may be at greater risk from injudicious venesection than from their polycythaemia. Despite an established literature on the subject, patients are frequently put at risk from acute volume depletion and chronic iron deficiency. This article aims to clarify some of the issues surrounding venesection and to set out guidelines ...