416 THE STUDY OF ANIMAL LIFE CHAP. 



Latin imposed, and it cannot be doubted that his works 

 did something to prepare the way for the future reception 

 of the 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, sug- 

 gesting that heat and light are atomic movements, deny- 

 ing the existence of hard-and-fast lines (" Le vivant et 

 1'anime est une propriete physique de la matiere ! "), pro- 

 testing 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 characteristic contours ; 

 Buff on took an eagle's flight and saw the connected 

 range of hills,- ' 1'enchainement des etres." 



ERASMUS DARWIN (1731-1802), grandfather to the 

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

 thoughtful 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 unstable carriage of his own con- 

 trivance, prescribing abundant food and cowslip wine, 

 rich in good health and generosity. Comparing his 

 writings with those of Buffon, an acquaintance with which 

 he evidently possessed, we find more emotion and inten- 

 sity, 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 directness 

 .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 protec- 

 tion, and explained their progress as the result of their 



