6 AXIMALS CONTRASTED 



intimate structural and chemical composition, and, it may 

 be added most commonly, in consistence, there is a very 

 definite and marked difference between organic and in- 

 organic structures. 



Between animals and plants, on the other hand, there is 

 much less distinction. It seems a strange notion at first 

 that it is possible to confound an animal with a vegetable, 

 but it is true with respect to the lowest members of the two 

 kingdoms, many of which have been frequently passed by 

 the naturalist from one domain to the other, and for a long 

 time refused a permanent place in either. And the reason 

 is to be found in the fact that the essentials of life, so 

 to speak, which alone are manifested in these, are the 

 same in both. Both are born of a parent, and beget 

 offspring; both grow and develop, decay and die. And 

 in the lowest kind of animal there is nothing in external 

 appearance, no evidence of consciousness or volition, suffi- 

 ciently distinct to raise it into a place above vegetables. 



Nevertheless there are several well-marked characters 

 which prevent any great difficulty for the most part in 

 deciding to which kingdom a living being belongs. 



Perhaps the most essential of these is the presence or 

 absence of power to live upon inorganic material ; in other 

 words, to act chemically on carbonic acid, ammonia and 

 water, so as to make use of their component elements as 

 food. Indeed one ought probably to say that a question 

 concerning the capability of the lower kinds of animal to 

 live in this way cannot be entertained ; and that such 

 a manner of life should decide at once in favour of a 

 vegetable nature, whatever might be the attributes which 

 seemed to point to an opposite conclusion. The power of 

 living upon organic matter would seem to be less decisive 

 of an animal nature, for some fungi appear to derive 

 support almost entirely from this source. 



There is, commonly, a marked difference in general 

 chemical composition between vegetables and animals, 



