1 76 The Evolution Hypothesis. 



evolution must give some clear account, unless it alto- 

 gether fail as an explanation of organic nature. Mr. 

 Spencer is very much displeased if these powers im- 

 manent in the units should be confounded with the 

 " archaeus, vital principle, nisus formativus and so on." 

 He rejects such implication as unfounded, and givea 

 the explanation that " the proclivity of units of each 

 order towards the specific arrangement seen in the 

 organism they form, is not to be understood as result- 

 ing from their own structures and actions only ; but 

 as the product of these and the environing forces to 



which they are exposed In its complete form, 



the conception is that these specific molecules, .... 

 have for their form of aggregation in which their forces 

 are equilibrated the structure of the adult organism 

 to which they belong, and that they are impelled ta 

 fall into this structure by the co-operation of the en- 

 vironing forces and the force they exercise on one 

 another the environing forces being the source of 

 the power which effects the arrangement, and the pol- 

 arities of the molecules determining the direction." * 

 But this explanation does not satisfactorily clear up 

 the point: the environing forces may be the power 

 which effects the re -arrangement, but the inherent 

 proclivities of the units direct it. The winds may 

 drive the ship; the captain and crew steer it: the 

 course is determined by the intelligence on board. 



* Biology, Vol. I., Appendix, p. 488. 



