164 THE POPULAR SCIENCE MONTHLY 



pre-arranged plan, that at the beginning everything was determined in 

 detail and that all life is now following out the lines of that plan. 

 Comparing this with the other two theories, the rabbits have long hind 

 legs according to the Neo-Lamarckians because of the exercise they 

 received when running to escape the fox; their ears likewise became 

 longer because of the intentness with which they must guard against 

 enemies. To the Neo-Darwinian the elongate ears and hind legs are 

 due to changes in this direction in the germ cell, which changes nature 

 selected by means of the fox who ate all individuals failing to make 

 this change. To the teleologist it was planned in the beginning that 

 as the fox became swifter the rabbit should likewise become swifter and 

 more acute of hearing so that a proper balance should always be pre- 

 served between them. 



Bergson's view of creative evolution is vitalistic in that it, with 

 teleology, postulates a psychical force, which he calls the life impetus. 

 But it differs from teleology especially in its belief that life is not 

 bound by any prearranged plan, that it is free at all times to modify its 

 course, to change its direction. Life, according to this view, is like a 

 shell bursting as it flies, each fragment again bursting, and so on. The 

 life impetus is thus continually dividing. Just as the way a shell bursts 

 depends both upon the explosive force of the powder and the resistance 

 of the metal surrounding it, so the direction of life depends upon the 

 unstable balance of tendencies which it bears within itself and the re- 

 sistance it meets with from inert matter. It is as if the vital impetus 

 were trying to graft on the invariableness of matter the largest possible 

 amount of instability. 



According to the view of creative evolution, then, environment is a 

 force evolution must reckon with, but not its cause, as with the mech- 

 anists, while adaptation of the organism to its environment will explain 

 the sinuosities of the course of evolution, but not the general direction 

 and still less the cause of the movement itself. 



The problem confronting this vital impetus as it enters matter is 

 somewhere to gather energy with which to counteract the retarding 

 force of matter. At the surface of this earth the most available source 

 of energy is the sun's rays. So the problem before life was this — to 

 store this energy in suitable reservoirs so that it could be drawn upon 

 at any time and for any need such as movement or reproduction. It 

 succeeded in this by causing the kinetic power of the sun's rays to break 

 up the inorganic compounds into their separate elements and then re- 

 combine them into the potential energy of organic foodstuffs. At first, 

 doubtless, an organism thus gathered for itself the energy which it later 

 expended in free movements; this form may be symbolized in a crude 

 way by the infusorian, Euglena. This organism expends kinetic energy 

 in motion like any animal, but in addition to the ordinary animal 



