248 M. L. BASKERVILL. 



was a direct connection between the permeability for phosphoric 

 acid and a non-functional, i.e., an injured, condition of the 

 muscle. 



Among the papers describing the conditions for the perme- 

 ability of non-electrolytes, probably no other is so free from, 

 the objection that the permeability reported might be due to 

 injury as an article by Reid (6) in which he found that absorption 

 of glucose from the intestine is favored by the presence of salts. 

 Hiruma (4) in the paper referred to above reported that the 

 permeability of blood corpuscles for urea is not decreased but 

 probably increased by the presence of other non-electrolytes. 



Wertheimer (3) claimed that if frog skin had its inner surface 

 in contact with solutions of non-electrolytes more glucose would 

 penetrate than was the case when Ringer's solution was employed 

 in the same way. In an earlier paper (7) he had reported that 

 sugar passed through the frog skin into Ringer's solution if the 

 sugar was in contact with the inner surface of the skin and the 

 Ringer's solution on the outer surface, while no sugar passed if 

 the direction of the skin was reversed. The durations of the 

 experiments were fifteen hours or more. Bauer (8) objected that 

 Wertheimer secured more permeability to sugar under the 

 conditions that are more injurious to the skin; that is, with 

 sugar in contact with the inner surface of the skin. In his last 

 paper Wertheimer (9) has again stated that if a non-electrolyte 

 bathes the inner surface, frog skin is permeable to sugar; if an 

 electrolyte bathes the inner surface, it is impermeable. This is 

 just the condition that Bauer maintains is most injurious, so 

 some evidence as to the state of the skins is needed. 



Most of the writers mentioned confirm the influence of electro- 

 lytes in favoring the permeability of tissues to other electrolytes. 

 The evidence in regard to their effect on the permeability of 

 tissues to non-electrolytes is both more meagre and more con- 

 flicting. Since the permeability of frog skin to urea has been 

 shown in the preceding paper (10) to be decidedly influenced 

 by the kind of salts in contact with the tissues, the writer wished 

 to see what effect the absence of electrolytes, or the presence of 

 another non-electrolyte would have on the penetration of the 

 non-electrolyte, urea. 



