324 C03 MIC 1 'JUL OSOPJl Y. [pt.il 



time currently used in senses strictly analogous to those in 

 which tney are here employed. As we shall presently see, 

 the phenomena of organic kfe are those in which both the 

 primary and the secondary characteristics of Evolution and 

 Dissolution are most conspicuously exemplified. Especially 

 in the career of the animal organism, these complementary 

 processes are manifested in groups of phenomena that are 

 more easily generalized and more immediately interesting 

 than any others of like complexity ; and to these groups of 

 phenomena the terms Evolution and Dissolution have long 

 been popularly applied. 



On a superficial view it may now seem as if we were ready 

 to proceed, in the next chapter, to describe in detail the 

 process of Evolution, as exemplified in that most gigantic 

 instance of concentration of matter and dissipation of motion, 

 — the development of our planetary system, by condensation 

 and radiation, from ancestral nebulous matter. In this 

 origin, by aggregation, of our system of worlds, and in that 

 ultimate dissipation of it into nebulous matter which sundry 

 astronomic facts have long taught us to anticipate, we shall 

 presently find a complete and striking illustration of the 

 dynamic principles herein set forth. But we are not yet 

 quite prepared to enter upon the consideration of these 

 phenomena. We need but remember that in the develop- 

 ment of the solar system, with its mutually dependent 

 members sustaining complex and definite relations to each 

 other, much more is implied besides concentration of plane- 

 tary matter and diffusion of molecular motion in the shape of 

 heat; we need but remember this, and we shall see that 

 some further preliminary study is requisite. While, indeed, 

 the primary characteristics of Evolution and Dissolution are 

 those which are expressed in the pair of definitions above 

 given, and which it has been the object of the foregoing 

 inquiry to illustrate ; there are also, as just hinted, certain 

 secondary characteristics which it is equally necessary to 



