6oo 



THE BEGINNINGS OF LIFE. 



which subsequently modify the forms and structures of 

 Organisms in the following table : — 



Primarily 

 determined by 



CRYSTALS - - - Polarity. 



Organisms 



Polarity ■ 



(Epliemeroniorphs) . 



Subsequently modified by 



Ncttitre of 

 forms affected. 



External 

 changes H 

 Polarity. 



Internal 

 changes + 

 Polarity. 



Eph.emeromorplis 



and Species. 

 Species. 



a. Leading to important 



changes r/"?"ll"! Ephemeromorphs. 



(a. Direct influence - • 



] b. Indirect influence 

 V (' use and disuse') - 



changes 



Leading to important 

 and permanent al- 

 terations which be- 

 come transmitted - 



Leading to individual 

 differences, some of 

 which are intensi- 

 fied and made per- 

 manent by Natural 

 Selection 



3. Changes occasioned by ' crossing ' -f 



Polarity ■ 



Species. 



Species. 

 Species. 



* This word is used in the sense in which it is employed by Mr. Spencer, who says : ' If we 

 accept the word polarity as a name for the force by which inorganic units are aggregated into 

 a form peculiar to them, we may apply this name to the analogous force displayed by organic 

 units. But as above admitted, polarity as ascribed to atoms is but a name for something of 

 which we are ignorant ... we simply substitute the term " polarity" for the circuitous expression, 

 "the power which certain units have of arranging themselves into a special form." ' (' Principles 

 of Biology,* 1864, vol. i. p. 181.) 



It should not be forgotten, moreover, that Natural 

 Selection in its most general sense has reference to that 

 co-ordinating power in Nature whereby the fittest of 

 all organisms, of whatsoever kind and howsoever pro- 

 duced, tend to be perpetuated ; whilst Natural Selection 

 in its more special sense is an agency which Mr. Darwin 

 has shown to be capable of ' producing fitness between 

 organisms and their circumstances' by perpetuating 

 and intensifying any minute variations of a favourable 

 nature^. The latter is, however, only one amongst other 

 agencies which are capable of giving rise to specific 

 transmutations, although Mr. Darwin often speaks of 

 ' See p. 573. 



