THE DYNAMICS OF ADRENAL FUNCTIONAL ACTIVITY. 31 



depleted and collapsed, the blood in them having been drawn 

 internally: i.e., toward the great abdominal trunks. Again, 

 the intensity of the pain seems to indicate not mere engorge- 

 ment, but inordinate, disruptive, centrifugal, pressure, for 

 which mere relaxation of the vascular walls cannot account. 



On the whole, we are forced to conclude that there must 

 be an overpowering display of centripetal energy from the pe- 

 ripheral capillaries, arterial and venous, as soon as the supra- 

 renal secretion fails to indirectly hold the central vascular walls 

 up to their normal tone. That it is mechanical is suggested by 

 its mode; that it enters into the domain of hydrokinetics is 

 evident; and that loss of the normal equipoise between two 

 forces forms the basis of the process affirms itself on all sides. 

 The solution of the problem suggests itself when we recall, 

 besides the fact that the total sectional area of the capillaries 

 is seven hundred times that of the aorta, the manner in which 

 the capillaries are affected when muscular vessels are dilated. 

 The blood in them, as we have seen, is compressed by the 

 resiliency of their walls and the surrounding tissue, neuroglia, 

 etc., and literally floods the abdominal organs. Indeed, the 

 peripheral system contains as many sources of pressure as there 

 are capillary tubes in it enough many times to account for 

 all the mooted points just reviewed. 



To illustrate the violence of the power exerted in this con- 

 nection, we may refer to the principle of hydrokinetics, Pas- 

 cal's principle, which underlies the whole mechanical process. 

 This physicist completely filled a strong cask with water, closed 

 it hermetically, then inserted the end of a long, narrow, and 

 close-fitting glass tube through a hole in one of the staves. 

 Into the upper end of the tube, which stood upright, he then 

 slowly poured water. Long before the tube had been filled the 

 cask burst, owing to the excessive pressure within its walls. 

 How was this pressure exercised? "The pressure of a fluid 

 being due to its weight," the pressure in the upper layers of 

 the water in the tube was slight, while that in its lower layers 

 had increased in proportion with its distance from the top, 

 since "pressure at any point in a liquid varies as its depth/' 

 "A pressure exerted on a fluid inclosed in a receptacle" being 

 "transmitted undiminished to every part of that receptacle, 



