On Cutaneous Absorption* 299 



The urine, on his entering the bath, was pale, and suf- 

 fered no change by the addition of the alkali. On his 

 leaving the bath, the urine was again discharged ; and, 

 though it was not perceptibly tinged, instantly turned 

 of a bright-red when the potash was added. Five 

 hours after the experiment, the urine gave a deep-red 

 with the test; and the portion discharged the follow- 

 ing morning was sensibly reddened by the alkali. 



Reflecting on the results of the foregoing experi- 

 ments, I can account for them in no other way than on 

 the supposition that the colouring matter of madder en- 

 tered the system in consequence of its external applica- 

 tion ; and, until a more satisfactory way of accounting 

 for them be known, the doctrine of Cutaneous Absorp- 

 tion must be considered as placed beyond the reach of 

 controversy. 



In detailing my experiments, I have maintained as 

 rigid an adherence to truth, as my knowledge of lan- 

 guage would allow me. Every one knows how difficult 

 it is, by means of words, to give precise ideas of co- 

 lours. I have used the expressions purplish-broxvn and 

 cranberry -red. Different language would probably 

 have been adopted by a different experimenter ; and it 

 might, perhaps, more happily have expressed the ideas 

 intended. But words cannot alter an impression made 

 on the organ of vision. 



In attending to the results of my experiments, I have 

 not trusted merely to my own eyes. Many of my 

 friends have examined the different portions of urine 



