47 2 Organic Physics. [June, 



stituents. That it constantly does so we are well aware, and its 

 vigor in this respect is in close accordance with the vigor of vi- 

 tality. So much life action is represented by so much chemical 

 action. Chemical waste of the tissues accompanies every exer- 

 cise of vitality. Yet if vitality be some super-physical process, 

 some miraculous energy by which life is sustained and growth 

 proceeds, why is oxygen so absolutely necessary to its perform- 

 ances ? Why does chemical action necessarily accompany it? 

 The more closely we look into the matter the more evident it be- 

 comes that there is no such energy in existence as a special vital 

 force, and that chemical affinity is the only energy active in or- 

 ganic processes. 



Oxygen is much more than the scavenger of the organic body. 

 ' It is its quickener. It is the life-giver to which all vitality is due. 

 Its mode of action is undoubtedly destructive. But in destroying 

 old constructions it yields the energy through which alone recon- 

 struction can be effected. It is eating into life with an insatiable 

 appetite, yet in doing so it gives off energies which constantly 

 create new life. In the vegetable world the energy of the solar 

 rays supplies the force necessary to the first step in organic syn- 

 thesis, but oxygen does all the rest. Two opposite energies are * 

 constantly at work — chemical analysis and chemical synthesis — 

 and the former is absolutely necessary to every step of the latter. 

 Oxygen is incessantly engaged in the plant, breaking down its 

 molecules into simpler forms. But in doing so it yields energy 

 which is exercised in the formation of new and more complex 

 molecules. Every step of analysis is followed or accompanied by 

 a step of synthesis. All the energy yielded by oxidation in the 

 plant is thus employed, and step by step organic chemistry ad- 

 vances, until the proteid molecules of protoplasm are finally pro- 

 duced. 



In animals the life process does not differ essentially from that 

 of plants. Yet chemically animals begin where plants leave off. 

 The highest chemical product of plants serves as the nutriment of 

 animals. Their principle of action is the same. Every act of 

 chemical synthesis in both is preceded, or accompanied, by an act 

 of analysis. Every step of a portion of matter up stairs is based 

 upon a step of some other portion of matter down stairs. But in 

 animals the process begins near the top of the stairs. Only a few 

 steps can be made upwards ; many steps can be made downwards. 



