REACTIONS IN LIVING MATTER 



tion from the cell. On the other hand, we may 

 keep a crystal of lifeless matter in a glass tube 

 carefully shut up from all exchange of substance 

 with the external world for as many years as we 

 like. The existence of this crystal will continue 

 without end and without change of any of its 

 properties. There is no known living organism 

 which could remain in a dry resting state for an 

 infinitely long period of time. The longest lived 

 are perhaps the spores of mosses which can exist 

 in a dry state more than a hundred years. As a 

 rule the seeds of higher plants show their vital 

 power already weakened after ten years ; most of 

 them do not germinate if kept more than twenty to 

 thirty years. These experiences lead to the opinion 

 that, even dry seeds and spores of lower plants 

 in their period of rest of vegetation continue the 

 processes of metabolism to a certain degree. This 

 supposition is confirmed by the fact that a very 

 slight respiration and production of carbonic acid 

 can be proved when the seeds contain a small 

 percentage of water. It seems as if life were 

 weakened in these plant organs to a quite im- 

 perceptible degree, but never, not even tempo- 

 rarily, really suspended. 



Life is, therefore, quite inseparable from 

 chemical reactions, and on the whole what we 

 call life is nothing else but a complex of in- 

 numerable chemical reactions in the living sub- 

 stance which we call protoplasm. It must be 



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