91 



went only to prove, how much moisture was per- 

 spired, without affording- any information as to 

 the quality and nature of the perspired matter. 

 According 1 to the mean of these experiments 4-j 

 pounds per day, were perspired from the skin. 

 The secretion was most abundant during the time 

 of digestion, and least of all, immediately after 

 meals. CRUIKSHANK having confined his hand 

 in a glass, collected the water which transpired, 

 and found it to be very pure. In the air, a por- 

 tion of carbonic acid was found, which in all pro- 

 bability had been formed by the operation of the 

 air on the transpired matter, as the volume of the 

 air had not increased. As he obtained more water 

 in a low temperature than in a high one, he con- 

 cluded, that the transpiration of the skin was 

 greater in a low temperature; but it seems that 

 he did not recollect, that the more water was 

 condensed on the glass by cold, the greater be^ 

 came the power of the inclosed air to receive 

 evaporating water, when it was warmed again 

 by the hand. THENARD collected the matter 

 of transpiration in flannel shirts, and found, that, 

 after extracting it with water, and then evapor-r 

 ating that water, it produced an acid, saline, 

 syrupy extract, the free acid of which he consi- 

 dered as acetic, in consequence of an experiment 



