10 A ilANUAL 



the consideration of organic bodies, under which 

 head our new acquaintance is, we find, inckided. 



These organic bodies are divided into two por- 

 tions called animals and vegetables, but we have 

 seen that to form a legitimate division we must get 

 a definite idea of more characters which are peculiar 

 to each class : what then distinguishes an animal 

 from a vegetable ? You will say that common sense 

 shows you the difference between a cow and a cab- 

 bage — it is impossible to confound them. Very 

 well, but what does common sense say about a 

 sponge ? I have a work on Physiology, published 

 onl}^ four years ago, in which it is stated that our 

 most distinguished naturalists are still divided on 

 this point. Now one mark by which we recognise 

 an object as an animal, distinguishing it thereby 

 from a vegetable, is the fact of its having a distinct 

 cavity set apart for its organs, as the skull for the 

 brain, the stomach for the digestive organs, the 

 chest for the lungs — whilst in plants the respiration, 

 for instance, tliat is the reception and rejection of 

 the air necessary to their growth, is carried on by 

 means of infinitely extended surfaces, represented 

 by their leaves : so, too, animals generally grow by 

 adding new matter to themselves, which only keeps 

 up their definite form, whilst trees and flowers per- 

 l^etually put out new branches and roots without 

 an}^ very definite limit. Again, vegetables feed on 

 inorganic substances, lime and so forth, and animals 



