

THE PERMEABILITY OF FROG SKIN TO UREA. 

 II. THE EFFECT OF DEXTROSE AND SUCROSE. 



M. L. BASKERYILL.i 



INTRODUCTION. 



Loeb (i) in a series of papers on the passage of potassium 

 through the membranes of Fundulus eggs demonstrated that this 

 substance would pass through in the presence of other electrolytes, 

 but failed to do so with various non-electrolytes. The explana- 

 tion that he offered and termed the "salt effect" could apply 

 only to electrolytes. 



Since the experiments of Loeb on potassium, there has been 

 a good deal of other work comparing the permeability of tissues 

 to electrolytes in the presence of other electrolytes and in the 

 presence of non-electrolytes. Hoeber and Memmesheimer (2) 

 showed that basic dyes enter red blood corpuscles if dissolved 

 in salt solutions, but not if they are dissolved in sugar or glycocoll 

 solution. Wertheimer (3) confirmed the need of electrolytes for 

 the penetration of basic dyes through frog skin. Hiruma (4) 

 reported that blood corpuscles take up less ammonium and 

 alkaloid salts from a sugar solution than from a salt solution, 

 while more salicylate or thiocyanate is taken up from the sugar 

 solution. With frog muscle he found that basic dyes, alkaloid 

 salts, salicylate, and thiocyanate have their penetration favored 

 by sucrose as have also iodide and acid. The sugar checked 

 only sodium hydroxide. 



Embden and Adler (5) noted that if frog muscles were im- 

 mersed in isotonic sugar solution, phosphoric acid would pass 

 out, and the muscles would lose their contractility, although 

 even after a stay of several hours in the sugar solution they 

 would recover upon being again placed in Ringer's solution. 

 Phosphoric acid was also given off in Ringer's solution if the 

 muscles were fatigued or injured. The authors believed there 



'From the Laboratory of Physiology, University of Pennsylvania; the Marine 

 Biological Laboratory, Woods Hole; and the School of Medicine, University of 

 Texas, Galveston. 



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