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The following Paper was then read :— 



ON THE MORE DISTINCTIVE CHARACTERS OF ANIMALS AND 

 VEGETABLES. BY J. D. HEATON, M.D., OF LEEDS. 



The object proposed in this paper is to notice, briefly, 

 the various particulars in which animal beings are regarded 

 by naturalists as most remarkably differing from those which 

 possess the inferior organization of a vegetable, and to 

 show that, in respect of each of these distinctions, excep- 

 tional instances occur in the case of some species, so that 

 none of these are capable of affording grounds for an 

 exact scientific definition between the two great kingdoms 

 of organized nature, and that such a definition cannot be 

 established. 



1. The first points of difference mentioned as generally 

 pevailing between plants and animals, were the evident 

 particulars of form, size, and duration of existence. The 

 animal usually presents a bilateral symmetry of form, being 

 divisible along the median line into two halves of similar 

 outline ; and its limited number of similar organs and parts 

 entirely differs from the complex and irregular branching 

 of a plant. But, to mention no other exception to this 

 general rule, the ramified form of Polypipherae, entirely 

 resembling that of a vegetable, though unquestionably pos- 

 sessing an animal nature, sufficiently shows that this ground 

 of distinction is far from universal. In connexion with the 

 more definite form of animals, may be noticed their more 

 limited size and duration of existence, A forest tree may 

 continue to live and flourish for centuries, gradually in- 

 creasing in size throughout this long period ; an animal, 

 on the other hand, soon arrives at its full growth, and its 

 entire existence is limited to a definite period. But in these 

 respects, likewise, the animal zoophytes entirely depart from 



