2i 4 PHYSICAL BASIS OF CIVILIZATION 



sive internal energy in the preceding stage has 

 caused some atoms and molecules of both the primary 

 and secondary group of elements above named to fly 

 apart beyond the reach of the sum total of all the 

 affinities within the mass of which they were a 

 part, then they may be said to belong to a class of 

 substances intermediate between living and non- 

 living. 



Between these two outer limits living sub- 

 stances may be said to be continuously changing 

 their chemical and structural compositions, and 

 simultaneously their state of aggregation. Thus the 

 gaseous portions tend unceasingly to condense 

 into liquids. The liquids, while continuously pass- 

 ing into the gaseous state, are likewise constantly 

 solidifying. The solids are unceasingly being re- 

 solved into liquids, etc. These changes are accom- 

 plished by the before-mentioned continuity of the 

 process of balancing and unbalancing of attractions 

 and repulsions. 



Could the most extravagant imagination of the 

 author of the Arabian Nights have invented con- 

 ditions so wonderfully favorable to the production 

 of an infinitely protean variety of forms which 

 simultaneously serves as a means for successfully 

 defending life against the danger, to which it is 

 continuously exposed, of being destroyed by the 

 tendencies antagonistic to its processes residing in 

 the environment ? This defense is obviously accom- 

 plished by the power of producing an infinite variety 



