Notes on Organic Chemistry. 431 



so that a mineral body may frequently be exposed to consi- 

 derable heat, or to the action of powerful substances without 

 suffering change. We have such a material in glass, which is 

 softened, but not changed, by being made red hot, and which, 

 when shaped into a bottle, will contain powerful acids that would 

 speedily destroy wood, or dissolve ordinary metals. In the 

 organic world, we not only find highly complicated substances, 

 but generally such as possess little stability, which are easily 

 decomposed, or changed, by heator by chemical re-agents. Bodies 

 in this condition of mobility are essential to the process of 

 organic life, just as other bodies remarkable for stability are 

 essential to the construction of the strong framework of the 

 globe. Vitality is only exhibited (in connection with organism) 

 so long as active chemical and other changes occur; and pro- 

 cesses of growth differ from processes of decay, in the rate at 

 which they progress, and in the accommodation of their speed 

 to that of other processes going on in the same creatures at 

 the same time. 



In contemplating a living organism, we observe growth by 

 accession of particles taken in from without, and modified 

 according to the special requirements of the case. But in each 

 organism portions of that which is taken in will be discarded 

 as icaste, and portions of the matter forming the creature will 

 become effete, and be discharged by a machinery more or less 

 complex, according to the rank of the organism. 



Formerly it was supposed that the mode in which oxygen, 

 hydrogen, nitrogen, carbon,etc, werebuiltup in living organisms, 

 differed entirely from anything that could be accomplished by 

 purely chemical and physical means. "Life"''' was conceived 

 to be a mysterious principle, changing, according to its own 

 wants, the character and action of physical and chemical forces. 

 Men of great authority thought so while chemistry was either 

 occupied with analysis (the taking of compounds to pieces), or 

 with building up new compounds, so simple as to present no 

 resemblance to those produced by living beings. Now, 

 chemistry has not only entered upon the path of synthesis, or 

 composition, but it has made such great advances therein as to 

 justify the belief that all the chemical compounds found in the 

 organic world have had their origin purely and simply under 

 the action and guidance of chemical laws. 



No organic fife has yet been proved to exist, except as a 

 consequence of previous life, standing towards it in a more or 

 less obvious parental relation. Science has done nothing — 

 perhaps never can do anything — in the way of showing how 

 life began ; but having certain living beings before us, we can 

 trace their offspring from their first germs to their completest 

 forms. We do not know why or how life is connected with 



