40 THE DATA OF BIOLOGY. 



body, than it is out of the body.* Thus, to carry further the 

 simile used above, the atoms of hydro-carbons and oxy-hydro- 

 carbons contained in the tissues, are, like bricks on end, not in 

 the stablest equilibrium, but still in an equilibrium so stable, 

 that they cannot be overthrown by the chemical and thermal 

 forces which the body brings to bear on them. On the other 

 hand, being like similarly-placed bricks that have very nar- 

 row ends, the nitrogenous atoms contained in the tissues are 

 in so unstable an equilibrium that they cannot withstand 

 these forces. And when these delicately-poised nitrogenous 

 atoms fall into stable arrangements, they give impulses to 

 the more firmly-poised non-nitrogenous atoms, which cause 

 them also to fall into stable arrangements. It is a 



curious and significant fact, that in the arts, we not only 

 utilize this same principle of initiating extensive changes 

 among comparatively stable compounds, by the help of com- 

 pounds much less stable ; but we employ for the purpose 

 compounds of the same general class. Our modern method 

 of firing a gun, is to place in close proximity with the gun- 

 powder which we wish to decompose or explode, a small por- 

 . tion of fulminating powder, which is decomposed or exploded 

 with extreme facility ; and which, on decomposing, communi- 

 cates the consequent molecular disturbance to the less-easily 

 decomposed gunpowder. When we ask what this fulminating 

 powder is composed of, we find that it is a nitrogenous salt. 



Thus various evidences point to the conclusion, that besides 

 the molecular re-arrangements produced in organic matter by 

 direct chemical action, there are others of kindred importance 

 produced by indirect chemical action. Indeed, the inference 



* May it not be well to inquire whether alcohol is not, in a greater or less 

 measure, transformed in the body into acetic acid ? If, when in contact with 

 changing nitrogenous matter, in presence of oxygen, alcohol undergoes this 

 transformation out of the body, it seems not improbable that it does so in the body 

 especially as the raised temperature which aids the change in the one case exists 

 HI the other. It would be out of place here to set down the sundry facts which 

 countenance this hypothesis. I may say, however, that it apparently removta 

 some of the difficulties which at present perplex the question. 



