8 ARISTOTLE AS A BIOLOGIST 



that the past generation has made : life produces organi- 

 i zation, and not organization life. Again, in certain 

 - chapters which are by no means the least interesting of 

 the book, he shows, 1 after the fashion of the engineer, 

 and from the experience of the bridge-builder, 2 how the 

 principles of stress and strain are concerned in the fabric, 

 and in the physiology, of the organism ; how physical 

 and mechanical relations alter in the organism with 

 'increasing bulk; 3 and how incident forces of gravity, 

 growth, and pressure control or determine the shape of 

 leaf and bone and single cell. Under the guidance of 

 a wholesome restraint, a whole school of morphologists, 

 Roux's school of Entwickelungsmechanik, are now investi- 

 gating these self-same problems, and so bringing to the 

 help of morphology some of those physical concepts 

 which began to be the stock-in-trade of the physiologists 

 when Majendie wrote his Lemons sur les phenomenes 

 physiques de la Vie (1830). 



In the Ethics, Spencer undertakes to establish ' rules of 

 right conduct ' on a scientific basis, and he does not mini- 

 mize the difficulty of getting rid of ' supernatural ethics ', 

 nor of forming a science of ' what ought to be '. Neverthe- 

 less, he does his best to connect absolute Ethics with his 

 universal formula of cosmic evolution and equilibration. 

 Ethics must be based on science, and not on metaphysics. 

 There is, he holds, not only an Ethic for all reasonable 

 beings, but a principle of Ethic for all living things ; life 



1 As in an earlier essay on The Law of Organic Symmetry, 1859. 



2 Even in his Sociology, where he discusses the place of the pontifices 

 in an archaic priesthood, he seems to dally with peculiar affection 

 over these old bridge-builders. 



< * A curious corollary, or case in point, is found in the fact that 

 definite limits are set to the size of a terrestrial animal, and still more 

 to that of a flying bird, while the aquatic animal, comparatively im- 



\ mune from gravity, increases in locomotive speed, as a ship does, the 

 bigger it becomes (Princ. of Biology (2nd ed.), i. 156). 



