THE PERMEABILITY OF FROG SKIN TO UREA. 



253 



Reference has been made to the greater permeability to urea 

 in sugar solutions if the exposure is prolonged beyond three or 

 four hours. Table VIII. contains typical results showing more 

 penetration of urea in the solution of pure dextrose than in the 



TABLE VIII. 



2/27/25. 



Isotonic Dextrose + Ringer's Solution. 



Per Cent. 



Dextrose. Mg. Urea. 



50. .. . . 4-14 



75 3-30 



85 4.80 



90 3-18 



95 4-20 



100 10.32 



Ringer's Solution. 



Mg. Urea. 



6.60 

 9.72 

 7.98 



3-18 

 4.98 

 6.66 



CHART I. The chart represents the composite results obtained in ten experi- 

 ments. 



The solid line represents the amount of urea in milligrams penetrating the 

 skins in the Dextrose-Ringer's mixtures. 



The broken line represents the amount of urea in milligrams penetrating the 

 skins in the control experiments when Ringer's solution alone was used. 



The dotted line represents the percentage of permeability on the basis of the 

 permeability with Ringer's solution alone, which is taken to be 100 per cent. 





18 



