of the University of Pennsylvania. 87 



In general, drugs in solution in oil (not oleates) 

 are absorbed by the normal human skin with greater 

 or less ease. On the other hand, drugs in aqueous 

 solution are not so absorbed. Thus we have shown 

 that salicylic acid in oil is absorbed by the healthy 

 skin, whereas in the similar application of salicylate 

 of sodium, which is practically insoluble in oil, we 

 have never been able to obtain evidence of cutane- 

 ous absorption. 



In this connection may be mentioned the fact, 

 which we believe has not hitherto been recorded, 

 that methyl salicylate (true oil of wintergreen) is 

 apparently absorbed by the human skin. If this 

 oil be gently rubbed over the arm, the presence of 

 salicylic acid in the urine is readily demonstrable at 

 the end of an hour after the application. We say 

 apparently absorbed, because the salicylate in ques- 

 tion is volatile, and consequently may be absorbed 

 by the lung surface. A series of control experi- 

 ments was instituted to determine this point. A 

 little pledget of cotton, saturated with oil of winter- 

 green, was suspended immediately beneath the nos- 

 trils in such wise that it did not come in contact 

 with the skin. The urine, which was found to be 

 free from salicylic acid at the beginning of the ex- 

 periments, constantly showed the presence of this 



