Effect of venous flow on frequency of venous vasomotion in the bat wing.

R contractions of veins are a prominent feature of the veins in the bat's wing. It has been suggested that the principle stimulus for this activity may be pressure within the vessel. That the distending force of blood pressure excites the activity of vascular smooth muscle has been pointed out by others.' This investigation was carried out to determine what changes in the frequency of vasomotion would occur as a result of increasing the volume of blood per unit of time delivered to a vein from the arterial vessels.