A DORSET DIARY 157 



The colouring of a large number of our species is quite 

 radiant after their honest English fashion. 



The great tit (also brilliant in his way) will always 

 get on in the world. He seems quite indeterminate 

 in his way of living, feeding on the ground like a finch, 

 in the trees like a tit, in the air like a fly-catcher, 

 hammering the bark like a creeper, and equally at home 

 in every calling. 



From this incalculable, indeterminate method of 

 getting his living, may we not assume that his species 

 is potentially more capable of variation than other more 

 highly specialized types ? The great tit, like the sparrow, 

 is in the mid-stream of evolution ; he is in the full 

 current of progress ; he has a future before him. I 

 will not attempt to go into the highly complex problems 

 of the causes and conditions of variation, of the gradual 

 (or sudden as sometimes happens) metamorphosis of 

 one species into another and usually higher (as the 

 history of the world shows) type. But one may say 

 with some confidence that the inventions or qualities 

 which have contributed more to the " differentiation 

 and integration " of life as it is at present than any 

 other have been the following : Increased mobility 

 (only very few of the heavily armoured types have 

 survived in smaller descendants confined within narrow 

 areas) ; the development of parental care (the seed- 

 bearing plants of the secondary period quite ousted 

 the spore-bearers) ; the power of combining for mutual 

 aid (the vast majority of modern vertebrates are social) ; 

 the growth of the brain and the nervous system (there 

 is an enormous difference between the brains of modern 

 mammals and the marsupials and monotremes of the 

 secondary period) ; the indomitable will to live and 

 all-roundness, by which I mean the avoidance of over- 

 specialization. The gorilla cannot progress because it 

 is over-specialized. This last was the great point of 

 Samuel Butler, who so well called mutations " happy 

 thoughts," and compared evolution with the develop- 

 ment of a fugue from a very simple subject. The 

 Admirable Crichtons have been the founders of great 

 houses and the heirs of the ages, and nature is against 



