The permeability of human skin to electrolytes

Abstract

It has been shown previously that the human skin is permeable to water, and that the actual permeation is under physiological control. The present investigation deals with whether the skin is entirely impermeable to electrolytes in solution. The method consisted of immersing the arm in solutions of varying conc. of LiCl and KI, and examin-ing the urine (and also the blood in some cases) before and at intervals up to 24 hrs. after immersion. To in-crease the circulation of blood in the skin and thus facilitate any diffusion, the experiments were carried out in a chamber heated to 75[degree]-93[degree] F, the solution being at approx. the same temp. A delicate spectrographic method was used for the determination of Li; I was estimated by a correspondingly delicate chemical method. In no case did the amount of Li or I in the urine (or blood when examined) collected after immersion of the arm exceed the extremely small amount originally present. Evidently the intact human skin is completely impermeable to electrolytes in simple solution. An exp. in which I ointment was rubbed on the skin showed a definite increase in the I content of the urine after application, and indicates that un-ionized I is absorbed.