189 



supposed aerial perspiration is very inconsiderable ; 

 and the air obtained is to be considered not as the 

 result of one, but of many experiments ; for we are 

 told, that after the first hour the hand was with- 

 drawn ; and there can be little doubt but that this 

 was several times repeated before the experiment 

 was closed. By so frequent an introduction of the 

 hand, it is very probable that small quantities of ad- 

 hering air would be repeatedly earned in, which is 

 confirmed by the observation of Mr Abernethy, that 

 the separation of the air was greatest on first intro- 

 ducing the hand *. He farther says, that when in 

 temperatures between 60 and 7O, he kept his hand 

 five hours in seven ounce measures of nitrogen gas, 

 confined in a jar over mercury, there appeared no 

 difference in the quantity of the air ; and on passing 

 lime-water into the jar, rather more than one ounce 

 of carbonic acid was produced, when no oxygen was 

 present. The same results, nearly, were obtained, 

 when hydrogen and other gases were employed f. 



15O. These experiments of Mr Abernethy have 

 lately been repeated in Philadelphia by Dr Klapp, in 

 the presence of Dr Woodhouse, Professor of Che- 

 mistry in that university ; and with completely dif- 

 ferent results. This gentleman carefully separated 

 all the adhering air from his hand and wrist, by mo- 

 ving them in different directions under the surface 

 of the mercury, for ten minutes, as Mr Abernethy 

 had done : they were then introduced into the in- 

 verted glass-vessel, filled with the same fluid, at tern- 



Essays, Surgical, &c. p. 112. f Ibid - P- 



