Abstract.The peripheral circulation in the duck during diving has been studied. Changes in peripheral blood flow were indicated by measuring the venous pressure‐rise in a branch of the femoral vein, when the main venous return was occluded. Electrocardiograms and arterial pressures were recorded simultaneously. Upon diving of the animals an extreme bradycardia was observed while the arterial pressure underwent only small changes. The slow drop in the arterial diastolic pressure during diving indicated a great reduction in the rate of emptying from the larger arteries. The peripheral blood flow determined from the degree of venous return was likewise found to be markedly reduced. It is concluded that diving induces an adjustatory shut down of the circulation through the whole limb. This explains the animals' ability to compensate for the extreme bradycardia in the maintenance of high systemic blood pressure, thus securing an ample circulation to the brain during asphyxia.