THE VIBRATORY SENSE 



governs it unceasingly. There is perfect adjustment, 

 without anything to interfere. The organism, en- 

 wrapped by the water, supported by it, warned by 

 its sense organs, regularly reacts according to the 

 indications it receives. It is entirely submissive to 

 them, for, in contrast to the higher vertebrates, it has 

 not the regulation brought about by the constancy 

 of animal heat. Its main psychology is based on 

 sensations of the moment. 



Fishes obey their many sensitive inclinations accord- 

 ing to circumstances. If we use a scientific expression, 

 we may say that they yield themselves, without any 

 restraint, to all their tropisms, to all the automatic 

 appeals produced and governed by the direct, im- 

 mediate action of the medium in which they live. In 

 order to preserve their organic well-being, they behave 

 according to the stimulus of the circumstance of the 

 moment, and immediately respond to the action of 

 the environment by a corresponding reaction, their 

 sensorial apparatus acting as a warning. What is 

 called " instinct " in them is nothing but this response, 

 the expression of the perfect harmony which unites the 

 living creature to its surroundings. 



The fish is a particularly sensitive creature. For 

 purposes of observation I have occasionally posted 

 myself in prominent places, points of rock or old 

 tree-trunks, looking out over a fairly considerable 

 depth of water, frequented by various species. Pro- 

 vided I made no movement, and appeared to be just 

 another object, I could for quite considerable periods 

 watch the comings and goings, the slightest inflections, 

 the most fleeting response to sensations. I could secure 

 a perfect picture of the intensity of life before me. 

 Below me, the fishes moved without displaying the 

 slightest uneasiness, going about their business with- 

 out the least sign of fear. Each species has its own 

 type of behaviour, but all are alike in the uniformity 

 and continuity of their action. We feel that all these 

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