CHAPTEK V. 



DISTINCTION BETWEEN ANIMALS, PLANTS, 

 AND INANIMATE MATTEK. 



The determination of a distinguishing feature between 

 animals and plants, and of the relationship between forms 

 of life and inanimate matter, has long engaged the attention 

 of naturalists and others. Many passages in Aristotle's works 

 show that he also considered this very difficult question. 



He probably had no knowledge of the lowest forms 

 of life, and his knowledge of some forms, such as, for 

 instance, jelly-fishes, sea-anemones, and sponges, was 

 comparatively slight. He observed, however, that some 

 animals resembled plants in certain respects, and that some 

 forms of life originated under circumstances such as to 

 suggest that they were generated from inanimate matter. 

 Having made observations of this kind, he made the follow- 

 ing important statements; which seem to show that he 

 believed in spontaneous generation {avTo/xaroi jEvsa-ii), or, as 

 it is sometimes called, abiogenesis, and in a continuous 

 gradation from inanimate matter to the highest forms of 

 life. He says : " Thus Nature passes by degrees from 

 inanimate things (a4'y%a) to living beings, so that owing to 

 their continuity the boundary between them escapes notice, 

 and there is an intermediate common ground. For, first 

 after the class of inanimate things comes the class of plants, 

 and each of these differs from the rest in seeming to partake 

 of life to a greater or less extent, and the whole class seems 

 to be alive compared with other bodies, but lifeless compared 

 with animals. The passage from them to animals is con- 

 tinuous, as I said before, for anyone would be quite at a loss 

 in deciding whether some marine forms of life are plants or 

 animals, for they are attached to the sea-bed, and many of 

 such forms of life die when they are removed from it,"* 

 Again, he says : " For Nature passes in an unbroken man- 



* H. A. viii. c. 1, S8. 2 and 3. 



