THE VITAL FORCE. 65 



force; "the probable primary source of the force ap- 

 pearing in the phenomena of vitality." He shows, 

 too, that there are many other forms of this kind of 

 matter besides the organic : the hydrated silicic acid, 

 for example, from which in geologic periods flint 

 appears to have been formed. He compares these 

 substances to water kept from freezing at a tem- 

 perature below 32, or to a saline solution more than 

 saturated with the salt, and ready to crystallize on 

 the slightest shock ; a condition of tension essen- 

 tially the same as that which is the great distinction 

 of the organic substance. But still we do not know 

 what way the organic state of matter may have 

 arisen in nature. We are equally in the dark, 

 indeed, as to the origination of any of the other 

 forces or arrangements of elements; and the entire 

 body of our knowledge must be advanced before we 

 can satisfactorily discuss it. The difficulty is in- 

 creased by the absolutely contradictory results, 

 hitherto, of the experiments made by different ob- 

 servers to ascertain whether organized bodies arise 

 in infusions of vegetable matter, without the presence 

 of germs from which they may be developed. Each 



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