398 THE STUDY OF ANIMAL LIFE CHAP. 



Thus Treviranus, who believed very strongly in the 

 influence of surroundings, distinguished two periods of 

 vita minima in youth and in old age during which 

 external conditions press heavily, from the period of 

 vita maxima in adult life when the organism is more 

 free. To some kinds of influence, e.g. mechanical pres- 

 sures, passive and sedentary organisms such as sponges, 

 corals, shell-fish, and plants, arc more susceptible than 

 are those of active life. 



The human organism, like any other, may be modified 

 by its environment. Those external influences which 

 touch body and mind are to us the more important, since 

 we have them to some extent within our own hands, and 

 because our lives are relatively long. Even if the changes 

 thus wrought upon parents are not transmissible, it is 

 to some extent possible for us to secure that our children 

 grow up open to influences known to be beneficial, shel- 

 tered from forces known to be injurious. 



As the influence of surroundings is especially potent on 

 young things such as caterpillars aiid tadpoles all care 

 should be taken of the young child's environment during 

 the earliest months and years, when the grip that externals 

 have is great. 1 



As passive organisms are more in the thrall of their 

 surroundings than are the more active, we may empha- 

 sise the importance of beauty in the home, that the 

 organism may be saturated with healthful influence 

 during the periods in which it is most susceptible. The 

 manifold endeavours which are made to improve and 

 beautify human surroundings are justified not only by 

 their results ideally stated in Emerson's well-known 

 poem of " Art," -but by the biological facts on which 

 they more or less unconsciously depend. There would be 

 more progress and less invidious comparison of ameliora- 

 tive schemes if we realised more vividly that the Fates 

 are three. Though it is not easy to appreciate the three 

 sides of a prism at once, of what value is liberty on 

 an ash-heap, or equality in a hell, or fraternity among 



1 Cf. Matthew Arnold's poem, " The Future," and Walt Whit- 

 man's " Assimilations." 



