334 



THE CHEMISTRY OF CREATION. 



simplest means. If a vessel is filled with water 

 in which some fresh-burnt lime has been slaked, 

 and the water decanted off clear which is now 

 what is commonly called lime-water and if then, 

 taking a glass tube, we breath some of the air 

 we are expiring from the lungs through it, we 

 shall have rapid evidence that a change of some 

 kind has taken place in this air in the altered 

 appearance of the pre- 

 viously clear and pellucid 

 fluid. It now becomes 

 quickly turbid and milky? 

 and eventually deposits a 

 whitish sediment. Air, 

 in its ordinary condition, 

 would not produce this 

 decomposition, whatever 

 it may be; for the li- 

 quid remains unclouded, 

 though a large volume of 

 air be passed through it 

 by a bellows. Therefore 

 the air we take into the 

 lungs has this striking difference from that we 

 expire from them, that while it produces no 

 alteration in the colour or composition of lime- 

 water, the latter decomposes it and renders it 

 turbid. It will be interesting now to inquire 

 What is the nature of this difference ? 



