The fact that varying degrees of tension exist within the tissues under normal conditions is obvious from the general knowledge of such phenomena as the gaping of wounds and the protrusion of tissues through defects in the capsules of organs or enveloping sheaths of fascia. The fact that secretions of the organs may accumulate to the point of considerable tension in a reservoir such as the gallbladder or the urinary bladder is well known to every surgeon. The degree of tension existing within the vascular system and the intracranial cavity is a well known measure of differentiation between health and disease. To appreciate the fact that relatively great pressure is at times exerted on living tissues under normal conditions, it is only necessary to realize that when walking a man weighing 185 pounds (84 Kg.) exerts on the soles of his feet from the weight of the body alone a