32 



CHAPTER I. 



ON THE PLACE OF MAN IN THE SCALE OF BEING. 



Distinction "between Animals and Plants. 



13. IN entering upon the general survey of the Animal Kingdom, which it 

 is desirable to take, before we consider in detail any particular member of it, 

 the question naturally arises, how is the Animal distinguished from the 

 Vegetable ? There is no difficulty in replying to this, if we keep in view 

 merely the higher tribes of each division; no one, for example, would be in 

 any danger of confounding a Whale with a Palnij or an Elephant with an 

 Oak. It is when we descend to the opposite extremity of the scale, that we 

 encounter the greatest difficulty ; from the circumstance, that the distinguish- 

 ing characters of each kingdom disappear, one after another, until we are 

 reduced to those which seem common to both. So completely is this the case, 

 that there are many tribes, which cannot, in the present state of our know- 

 ledge, be referred with certainty to either one division or the other. We are 

 accustomed to think of Animals as beings, which not only grow and reproduce 

 themselves, but also possess the power of spontaneously moving from place 

 to place, and are conscious of impressions made upon them: and we usually 

 regard Plants as beings which are entirely destitute of sensibility and of the 

 power of spontaneous motion, going through all their processes of growth, 

 reproduction, and decay, alike unconscious of pleasure and of pain, and devoid 

 of all power of voluntarily changing their condition. Such a definition is pro- 

 bably the most correct that we can employ ; but great difficulties lie in the way 

 of its application. There are many tribes which possess a general structure 

 more allied to that of beings known to be Animals, than to that of any Plants ; 

 and which yet present no decided indications either of sensibility or of volun- 

 tary power. Such is the Sponge, the fabric of which closely corresponds 

 with that of many Alcyonian Polypes, whose animality is undoubted; and yet 

 neither observation nor experiment has ever succeeded in proving that the 

 Sponge feels or spontaneously moves. Yet there are no known Vegetables, 

 to which it presents any near resemblance. On the other hand, there are 

 many vegetables that perform evident movements, which, at first sight, appear 

 to be spontaneous, as if they indicated sensibility on the part of the being that 

 performs them. Such movements, however, can in some instances (as in that 

 of the Sensitive-Plant, or of the Venus's Fly-trap), be referred to a sort of 

 mechanism, the action of which does not involve sensibility, and which may 

 be compared with the many movements (such as that of the heart) that are 

 constantly taking place in the bodies of the highest animals, without their 

 consciousness; and in other cases (as in the Oscillalorise) they are so rhythm- 

 ical, as to impress the observer with the idea, that they are rather the result 

 of some physical, than of any mental, influence. In this respect they corre- 

 spond with the motions of the constantly-vibrating cilia, which cover the sur- 

 face of the mucous membranes of Animals. 



14. However difficult it may be for us, owing to our imperfect knowledge, 



