2 MANUAL OF NATUEAL HISTOEY. 



characteristics will be, as far as practicable, of a 

 strictly Zoological nature; not that for a moment 

 we would, by so doing, wish to cast any slight upon 

 the other branch, which is undoubtedly the higher 

 and more philosophical of the two, but merely be- 

 cause it is not of so practical a nature, nor so univer- 

 sally applicable for general discrimination of forms, 

 and consequently less adapted for the purpose we 

 have in view. 



A succinct and exact definition of an animal, as 

 distinguished from a vegetable, is not an easy task. 

 The two kingdoms do not run into each other by 

 any means, but both appear to spring from a com- 

 mon root, viz., vitality; and, for some distance from 

 their origin, are so closely blended that a separation 

 is extremely difficult. Accordingly we find that 

 the lowest members of each group are, by different 

 writers, described as animals, or as vegetables, just as 

 their ideas happen to dictate. Linnaeus on this point 

 gave utterance to a celebrated axiom, viz., "Stones 

 grow, vegetables grow and live, animals grow, live, 

 and feel/' This, though perhaps true enough in the 

 main, is not sufficiently explicit, as it is difficult to 

 prove that Sponges, which are generally admitted 

 as animals, are possessed of feeling ; while again Sir 

 James Edward Smith argued, though quite on hypo- 

 thetical grounds, that plants might be endowed with 

 sensation, though in a very low degree, in which 

 opinion, however, he had but few followers. The 

 power of voluntary motion has also been brought 

 forward as a test, but such a criterion is alike futile 



