ORIGIN OF LIFE, SEX, SPECIES, ETC. 211 



on hand within the area where the conditions pre- 

 vailed, which were crudely outlined in the foregoing 

 paragraph. 



Before considering the origin of cells and of the 

 differentiation of these into somatic and repro- 

 ductive, it will aid comprehension to give some 

 attention to the nature of the elementary substances 

 which contribute the greater part of the material 

 and energy exhibited by life and its products. Oxy- 

 gen, hydrogen, and nitrogen are chiefly distin- 

 guished by the enormous excess of kinetic and 

 potential energy which they retain at the lowest 

 temperatures which have occurred since life began on 

 earth. This enormous reserve power contained in 

 each ultimate particle of these substances is highly 

 suggestive in connection with the nature and pro- 

 cesses of life. 



It is clearly the competent cause of those multi- 

 farious movements and changes which distinguish 

 living organisms in their simplest and smallest 

 parts, and even more in those larger complex organs 

 and tissues produced by the combinations and re- 

 combinations of cells in an apparently infinitely 

 progressive ascending scale. It is also a sufficient 

 reason, in connection with assimilation, secretion, 

 and excretion, of all those changes which occur in 

 any living individual, beginning with its birth and 

 ending after death with complete dissolution. In- 

 cluded in this series are the phenomena of conscious- 

 ness, thought, feeling, emotion, and conduct. 



