1897.] NATURAL SCIENCES OF PHILADELPHIA. 17 



molecules, and there may have been a long-continued process of de- 

 oxidation and formation of higher carbon and nitrogen compounds, 

 till true organic matter appeared and the chemistry of life came 

 fairly into play. 



I have but one further suggestion to offer. That is, that the con- 

 ditions favoring the development of organic material were transitory, 

 and no longer exist. If living matter were now swept from the 

 earth, it could not, in any probability, be restored. Its seed condi- 

 tions have passed away. They could not reappear in water of the 

 temperature of the present ocean and the existing chemical rela- 

 tions of inorganic matter. Organic chemistry emerged from a 

 vitally active stage of inorganic chemistry. It could not well arise 

 from the existing passive stage of inorganic chemistry. Fortunately, 

 conditions favoring the origin of organized matter are no longer 

 needed. Organisms have within themselves the power of inducing 

 new chemical action to an indefinite extent. A plant is a natural or- 

 ganic laboratory, within which new organic material is elaborated 

 from elementary constituents which exist abundantly in air and 

 water. From the plant the animal derives the more complex ma- 

 terial it requires. Thus the process goes continually on, and can 

 only be brought to an end by a fall in temperature below the point 

 requisite for organic chemism. How far in the future this will be it 

 is impossible to predict, but the reign of life, which has continued 

 for many millions of years upon the earth, will, in all probability, 

 continue for many millions of years to come. 



