PERSPIRATION. 649 



accurate accounts have beeiv kept, and where deception was not 

 so much practised, the urine was found not to exceed the quan- 

 tity of drink.* In a case of diabetes, related with much accu- 

 racy by Dr Gerard, the patient was bathed regularly during the 

 early part of the disease in warm water, and afterwards in cold 

 water : he was weighed before and after bathing, and no sensi- 

 ble difference was ever found in his weight.f Consequently, in 

 that case, the quantity absorbed, if any, must have been very 

 small. 



It is well known that thirst is much alleviated by cold bathing. 

 By this plan Captain Bligh kept his men cool and in good health 

 during their very extraordinary voyage across the South Sea. 

 This has been considered as owing to the absorption of water by 

 the skin. But Dr Currie had a patient who was wasting fast 

 for want of nourishment, a tumour in the oesophagus preventing 

 the possibility of taking food, and whose thirst was always alle- 

 viated by bathing ; yet no sensible increase of weight, but rather 

 the contrary, was perceived after bathing. It does not appear, 

 then, that in either of these cases water was absorbed. 



Farther, Seguin has shown that the skin does not absorb 

 water during bathing, by a still more complete experiment : He 

 dissolved some mercurial salt in water, and found that the mer- 

 cury produced no effect upon a person that bathed in the water, 

 provided no part of the cuticle was injured : but upon rubbino- 

 off a portion of the cuticle, the mercurial solution was absorbed 

 and the effects of the mercury became evident upon the body! 

 Hence it follows irresistibly, that water, at least in the state of 

 water, is not absorbed by the skin when the body is plunged into 

 it, unless the cuticle be first removed. 



This may perhaps be considered as a complete proof that no 

 such thing as absorption is performed by the skin ; and that there- 

 fore the appearance of carbonic acid gas, which takes place when 

 air is confined around the skin, must be owing to the emission of 

 carbon. But it ought to be considered, that, although the skin 

 cannot absorb water, this is no proof that it cannot absorb other 

 substances ; particularly that it cannot absorb oxygen gas, which 

 is very different from water. It is well known that water will 

 not pass through bladders, at least for some time : yet Dr Priest- 

 ley found that venous blood acquired the colour of arterial blood 



* See Rollo on Diabetes. f Ibid . ii. 73. 



