6 AXIMALS' COXTRASTED 



regard them, as sentient beings. Inherent power of move- 

 ment, then, although especially characteristic of animal 

 nature, is, when taken by itself, no proof of it. Of 

 course, if the movement were such as to indicate any kind 

 of purpose, whether of getting food or any other, the case 

 would be different, and we should justly call a being ex- 

 hibiting such motion, an animal. But low down in the 

 scale of life, where alone there exists any difficulty in 

 distinguishing the two classes, movements, although almost 

 always more lively, are scarcely or not at all more pur- 

 posive in one than the other ; and even if we decide on the 

 animal nature of a being, it by no means follows that we 

 are bound to acknowledge the presence of sensation or 

 volition in the slightest degree. There may be at least 

 no evidence of its possessing a trace of those tissues, 

 nervous and muscular, by which, in the higher members 

 of the animal kingdom, these qualities are manifested. 

 Probably there is no more of either of them in the lowest 

 animals than in vegetables. In both, movement is effected 

 by the same means ciliary action, and hence the greater 

 value, for purposes of classification, of the power to live 

 on this or that kind of food, on organic or inorganic 

 matter. As the main purpose of the lowest members of 

 the vegetable kingdom is doubtless to bring to organic 

 shape the elements of the inorganic world around, so the 

 function of the lowest animal is, in like manner, to act on 

 degenerating organic matter, "to arrest the fugitive 

 organized particles, and turn them back into the ascending 

 stream of animal life." And, because sensation and voli- 

 tion are accompaniments of life in somewhat higher animal 

 forms, it is needless to suppose that these qualities exist 

 under circumstances in which, as we may believe, they 

 could be of no service. It is as needless as to dogmatise 

 on the opposite side, and say that no feeling or voluntary 

 movement is possible without the presence of those tissues 

 which we call nervous and muscular. 



