2 88 The Study of Animal Life part iv 



doctrine of descent. He had a vivid feeling of the unity 

 of nature, throwing out hints in regard to the fundamental 

 similarity of different forms of matter, suggesting that heat 

 and light are atomic movements, denying the existence of 

 hard-and-fast lines — " Le vivant et I'animd est une propridtd 

 physique de la mati^re !" protesting against crude distinctions 

 between plants and animals, and realising above all that 

 there is one great family of life. Naturalists had been 

 wandering up and down the valleys studying their charac- 

 teristic contours ; Buffon took an eagle's flight and saw the 

 connected range of hills, — " I'enchainement des etres." 



Erasmus Darwin (1731-1802), grandfather to the 

 author of the Origin of Species, was a large-hearted, thought- 

 ful physician, whose life was as full of pleasant eccentricities, 

 as his stammering speech of wit, and his books of wisdom. 

 We have pleasant pictures of the philosophical physician 

 of Lichfield and Derby, driving about in a whimsical un- 

 stable carriage of his own contrivance, prescribing abundant 

 food and cowslip wine, rich in good health and generosity. 

 Comparing his writings with those of Buffon, an acquaint- 

 ance with which he evidently possessed, we find more 

 emotion and intensity, more of the poet and none of the 

 diplomatist. He approached the study of organic life on 

 the one hand as a physician and physiologist, on the other 

 hand as a gardener and lover of plants ; and, apart from 

 poetic conceits, his writings are characterised by a direct- 

 ness and simplicity of treatment which we often describe as 

 " common-sense." 



He believed that the different kinds of plants and animals 

 were descended from a few ancestral forms, or possibly 

 from one and the same kind of " vital filament," and that 

 evolutionary change was mainly due to the exertions which 

 organisms made to preserve or better themselves. He 

 showed that animals were driven to exertion by hunger, by 

 love, and by the need of protection, and explained their 

 progress as the result of their endeavours. Buffon under- 

 rated the transforming influence of action, and laid emphasis 

 upon the direct influence of surroundings ; Erasmus Darwin 

 emphasised function, and regarded the influence of the 



