Methods have been devised to bring microscopic amounts of fluid into contact with cutaneous connective tissue, under pressure or without pressure, in such a manner that it enters neither blood capillaries nor lymphatics directly. The take-up of fluid brought into contact with the tissues in this way has been measured and its characteristics studied. Elaborate control tests, here described and discussed, have indicated the possible errors in the employment of these methods.
Locke's or Tyrode's solutions brought into contact with the cutaneous tissues, by the method described and at atmospheric pressure, pass into the tissue intermittently. Forced into the skin by pressures of 1.0 to 2.0 cm. of water the take-up is still intermittent in character. From this it follows that either the absorption of interstitial fluid from localized regions is periodic or the movements of interstitial fluid are influenced by intermittent physiological changes.