8Q THE HUMAN LUNGS. 



tion is on the way in, and the air of expiration is on the way out, 

 but neither the one nor the other is a part of the living frame ; how- 

 ever deep either may be in the passages of the body, still it is not 

 indoors. The lining membrane or wall of the cell is the partition 

 between life and death ; inside the cell is vitality, outside of it, 

 dead nature : within it, the man lives ; without it, the universe envi- 

 rons him : the oxygen which is lost is missed from the outside, and 

 the carbonic acid which is found is on the outside also ; but on the 

 inside no corresponding observation has been made, or can be made ; 

 and it is a questionable inference whether carbonic acid, as such, 

 exists in the blood, or whether oxygen, as such, is there either. As 

 an account of the food of the blood, and of the excrements of the 

 blood, both external to the man, the chemical report is valid, but is 

 it a satisfactory statement of any changes in the blood itself circu- 

 >. lating in the system? Assuredly not; and let us here remark that 

 the terms of every subject should be in keeping with the subject ; 

 the things which are life's should be rendered to life, and those of 

 chemistry to chemistry. We cannot judge of the living, either by 

 the raw material which they pasture from the world, or by the re- 

 fuse which they leave behind them; or even by both together. 

 Organization is the one fact in organization; chemistry disappears 

 into it, and is seen no more as chemistry. The blood, as an organic 

 creature, into which all thiags stream, and from which the body 

 issues as the work of works, is the sole reality in our veins ; it is as 

 blood alone that its elements come before us. As well regard all 

 heroic actions as instances of muscular exertion, and these as powers 

 of lever and fulcrum, and other produce of mechanics, and not con- 

 nect them with the fountains of human nature, as make the living 

 union of all things in the blood into a congeries of chemical sub- 

 stances. Chemical indeed they are when they die and are experi- 

 mented on, but chemical is not their name while they are part and 

 parcel of our human blood. They must be addressed in the language 

 proper to organic life, or the keeping of their science will be violated 

 irretrievably. 



We the more insist upon this, because by a very natural insur- 

 gency, chemistry has of late years been pushing what are called its 

 conquests into the domain of physiology. But physiology has to 



