THE VIBRATORY SENSE 



quietly approached, for the slightest shaking of the 

 soil, transmitted to the water, is enough to put it to 

 flight; furthermore, the line with its float must be fitted 

 in such a way that there is no abnormal vibration ; fin- 

 ally, it must be struck sharply, for the slightest oscilla- 

 tion frightens it off at a great pace. It shows, better 

 than most fishes, how they are affected in various 

 ways by their sensations. Its indecision is only appar- 

 ent ; in reality it takes one decision after another, 

 but they work in different ways. Each time, the 

 creature obeys the sense which happens to be pre- 

 dominant; it conforms its conduct to that sense; and, 

 as the predominance varies according to the conditions 

 prevailing at the moment, it acts according to the 

 influence of that moment, and expends itself in a series 

 of automatic and successive obediences. 



The outer world is built up on the basis of the 

 sensations experienced. That of a bird of prey, in 

 which sight is predominant, is composed of shapes, 

 figures, and images. That of a dog consists largely 

 of odours and noises; its olfactory sense and acute 

 hearing dominate all the rest. That of a roach is 

 made up of tastes and vibratory waves. Transferring 

 to the water the sensations which the dog experiences 

 in the air, it conforms its behaviour to the indications 

 given by its two principal senses, those of savour 

 and vibration. It goes from one to the other, to which- 

 ever happens to be the stronger at a particular instant. 



The life of fishes is a collection of, and a compromise 

 between, continual reflexes. When we see these 

 creatures in the water and consider the ease and 

 flexibility with which they move about, we realize 

 that they are strictly adapted to their surroundings, 

 and that their organization accommodates itself com- 

 pletely to the conditions under which it is placed. 

 The expression " As happy as a fish in the water " 

 has become a proverb. And its behaviour is well 

 regulated because the water itself, the environment, 

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