56 LEISURE-TIME STUDIES. 



possess means for receiving and for acting upon sensations, 

 and that, in this light, they may be fitly compared with the 

 hydrae and all lower animals in which a nervous system has 

 not been demonstrated to exist. 



It is perfectly clear that the acts of these plants, and of 

 such animals as the hydrae and sea-anemones, must be con- 

 sidered of purely automatic kind. We cannot reasonably 

 suppose that consciousness, or a knowledge of why or how 

 the acts are performed, plays any part in the life-history of 

 such forms. And even if it be maintained that mere sensation 

 and consciousness in this case are identical or closely allied, 

 the latter quality must be so far removed in its nature from 

 the consciousness of humanity, as to render the comparison 

 quite inadmissible. The hydra and its neighbours are in 

 truth automata pure and simple, in that they are stimulated by 

 outward circumstances, and respond to such stimuli, without 

 possessing any appreciation of the why and wherefore of any 

 act of their lives. 



But that automatic acts may represent the whole life, or 

 a very large share of the actions of animals much higher 

 than these polypes, can readily be demonstrated. A centi- 

 pede, for example, when cut in halves, will exhibit lively and 

 independent movements in each half of its body, a fact 

 readily explained when we note that each joint of the 

 animal's body possesses a nerve-centre, which supplies the 

 surrounding parts with sensation. And if the central portion 

 of the nervous system of the animal be destroyed whilst its 

 body remains intact, the front portion of the body and the 

 front legs may stop at the sight of an object, whilst the legs 

 belonging to the portion lying behind the division of the 

 nerves, will continue to push the animal forwards. Here 

 the action of the hinder legs is purely automatic. But in the 

 insect-class we find many examples of automatic acts, per- 

 formed naturally, and which at first sight actually seem to 

 suggest the development of a high intelligence. The young 

 insect, liberated from its chrysalis state, and necessarily 

 destitute of all experience, performs at once and perfectly all 



