THE AXDIAL KINGDOM. 



At first sight animals and plants seem entirely distinct. 

 We say that animals move, have sensation, have organs of 

 feeding, of respiration, motion, etc., and that the plants 

 lack all these. When we contrast a cat and a cabbage 

 these and many other points of difference are at once 

 forced upon us, while the features in which they resemble 

 one another seem to be extremely few. If. however, we 



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carry our comparisons farther and take the lower forms 

 into account, we soon find that these distinctions fail. We 

 find many animals * which are as firmly fixed as any 

 tree, while we find many undoubted plants which move 

 through the water as freely as any fish. We find, again, 

 many plants which have evident powers of sensation. 

 House-plants in a window turn their leaves towards the 

 source of light; the leaves of the sensitive-plant droop if 

 they be touched; while the reproductive elements (zoo- 

 spores) of many low aquatic plants will recognize the 

 presence of and swim towards a trace of malic acid. On 

 the other hand, sensory organs are as poorly developed 

 in sponges, and in many Protozoa, as in most plants. 



* Frequently the term animal is restricted to members of the 

 group of mammals. Thus we hear one say 'animals and birds.' 

 This is not correct. A bird, a fish, or a clam is as truly an animal 

 as is a cat. 



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