ii DEVELOPMENT OF ANIMAL LIFE 135 



relatively stable, and counterfeit immobility so well 

 that we treat each of them as a thing rather than as a 

 progress, forgetting that the very permanence of their 

 form is only the outline of a movement. At times, 

 however, in a fleeting vision, the invisible breath that 

 bears them is materialized before our eyes. We have 

 this sudden illumination before certain forms of maternal 

 love, so striking and in most animals so touching, 

 observable even in the solicitude of the plant for its 

 seed. This love, in which some have seen the great 

 mystery of life, may possibly deliver us life s secret. It 

 shows us each generation leaning over the generation 

 that shall follow. It allows us a glimpse of the fact 

 that the living being is above all a thoroughfare, and 

 that the essence of life is in the movement by which 

 life is transmitted. 



This contrast between life in general, and the forms 

 in which it is manifested, has everywhere the same 

 character. It might be said that life tends toward the 

 utmost possible action, but that each species prefers to 

 contribute the slightest possible effort. Regarded in what 

 constitutes its true essence, namely, as a transition from 

 species to species, life is a continually growing action. 

 But each of the species, through which life passes, aims 

 only at its own convenience. It goes for that which 

 demands the least labour. Absorbed in the form it is 

 about to take, it falls into a partial sleep, in which it 

 ignores almost all the rest of life ; it fashions itself so 

 as to take the greatest possible advantage of its im 

 mediate environment with the least possible trouble. 

 Accordingly, the act by which life goes forward to the 

 creation of a new form, and the act by which this 

 form is shaped, are two different and often antagon 

 istic movements. The first is continuous with the 



