88 GENERAL BIOLOGY 



While the analysis of the processes involved in the metab- 

 olism of the living substance is difficult, and details are 

 somewhat uncertain and only the beginning and the end 

 steps have hitherto been traced, there is no doubt whatever 

 about a number of the main facts : 



1. That the organic life of the world is supported on 

 water, carbon dioxide and simple mineral salts, gathered 

 and assimilated by the green plant cell. 



2. That these mineral substances are of simple composi- 

 tion, are composed of but few elements united strongly, and 

 that they are very stable, and devoid of potential energy. 



3. That the non-nitrogenous substances first combined 

 under the power of the sun's rays, are compounds of a 

 higher order of complexity of less stability and of much 

 more potential energy. 



4. That the nitrogenous substances (proteins) are of 

 great diversity and of exceeding great complexity of struc- 

 ture, very unstable, and of very high potential energy. 



5. That protoplasm is a complex substance (not a single 

 chemical compound) , probably a mixture or combination of 

 various proteins, water, etc., so unstable it is impossible of 

 analysis for, to analyze it kills it, and death initiates changes 

 altering its composition. 



6. That the primary source of energy is the sun, drawn 

 upon by the green plants first; the supply for other organ- 

 isms is the potential chemical energy of manufactured carbo- 

 hydrates, proteins, and of free oxygen. 



Protoplasm, the physical basis of life, the living part of 

 every living thing, and essentially the same in its general 

 properties and functions in all, possesses in green plants the 

 capacity for developing chlorophyl, through the agency of 

 which the energy of the sun can be utilized in effecting such 

 analysis of simple mineral compounds and such synthesis 

 of more complex organic compounds as result in the storing 



