ii.j THE PLANT AND THE ANIMAL 109 



sectivorous plants, such as the Drosera and the Dionaea, 

 to seize their prey. The leaf-movements of the acacia, 

 the sensitive plant, etc., are well known. Moreover, 

 the circulation of the vegetable protoplasm within its 

 sheath bears witness to its relationship to the protoplasm 

 of animals, whilst in a large number of animal species 

 (generally parasites) phenomena of fixation, analogous 

 to those of vegetables, can be observed. 1 Here, again, 

 it would be a mistake to claim that fixity and mobility 

 are the two characters which enable us to decide, by simple 

 inspection alone, whether we have before us a plant or an 

 animal. But fixity, in the animal, generally seems like 

 a torpor into which the species has fallen, a refusal to 

 evolve further in a certain direction; it is closely akin to 

 parasitism and is accompanied by features that recall 

 those of vegetable life. On the other hand, the move- 

 ments of vegetables have neither the frequency nor the 

 variety of those of animals. Generally, they involve only 

 part of the organism and scarcely ever extend to the whole. 

 In the exceptional cases in which a vague spontaneity 

 appears in vegetables, it is as if we beheld the accidental 

 awakening of an activity normally asleep. In short, 

 although both mobility and fixity exist in the vegetable 

 as in the animal world, the balance is clearly in favor of 

 fixity in the one case and of mobility in the other. These 

 two opposite tendencies are so plainly directive of the two 

 evolutions that the two kingdoms might almost be defined 

 by them. But fixity and mobility, again, are only super- 

 ficial signs of tendencies that are still deeper. 



Between mobility and consciousness there is an obvious 

 relationship. No doubt, the consciousness of the higher 

 organisms seems bound up with certain cerebral arrange- 



1 On fixation and parasitism in general, see the work of Houuay, 

 La Forme et la vie, Paris, 1900, pp. 721-807. 



