PHYSICAL FORCES AND THE VASCULAR LINING *t

STRIKING similarities exist between the behavior of rivers and of blood vessels. Rivers erode their banks and deposit sediment to produce islands, thereby modifying the local and even distant geography. Similarly, the bloodstream probably determines certain features of the form and structure of the blood vessels, the heart and the valves. Discovery of the laws of flow, and study of the structural characteristics of the rock of the river bed, have made it possible to harness tremendous forces and to convert catastrophic floods and erosions into the blessings of irrigation and water power. Elucidation of the hydraulic principles in-volved in flow through the blood vessels, and an analysis of the structural propensities of the connective tissues comprising these, may similarly open the way to the control and even the prevention of some of the common vascu-lar diseases. It is generally held that the wide variety of forms of the blood vessels and their appendages is determined principally by the operation of genetic, inflammatory and degenerative processes.1 Unfortunately, experimental analysis of these processes is extremely difficult. Our recent studies have demonstrated that examination of the physical forces of the bloodstream, and of the responses induced in the vascular con-nective tissue, can explain certain structural characteristics of the vascular system.2"5 •Received for publication November 28, 1958