20 ro.Mi'AKATiyi; ANATOMY HKIXWI; CUVIMK 



are also groups of individuals which resemble one another 

 from generation to generation and are able to breed 

 together. These are species Buffon adheres to the genetic 

 definition of species and the species is a much more definite 

 unit than the genus, the order, the class, which are not 

 divisions imposed by us upon Nature. Species are definitely 

 discontinuous, 1 and this is the only discontinuity which 

 Nature shows us. Buffon put his views into practice in his 

 ///.vAv'/r *\<i//<;r//i\ where he describes species after species, 

 never uniting them into larger groups. \\'e have seen, 

 however, how the facts forced upon him the conception of 

 the " family." 



Buffon was no morphologist. lie left to Daubenton 

 what one might call the "dirty work" of his book, the 

 dissection and minute description of the animals treated. 



But Buffon was a man of genius, and accordingly his 

 ideas on morphology are fresh and illuminating. Few 

 naturalists have been so free from the prejudices and 

 traditions of their trade. He makes in the Discours sur la 

 Nature dcs Aniinanx'- a distinction, which Bichat and 

 Cuvier later developed with much profit, between the 

 "animal" and the "vegetative" part of animals. 3 The 

 vegetative or organic functions go on continuously, even 

 in sleep, and arc performed by the internal organs, 

 of which the heart is the central one. The active 

 waking life of the animal, that part of its life which 

 distinguishes it from the plant, involves the external parts 

 the sense-organs and the extremities. An animal is, as it 

 were, made up of a complex of organs performing the 

 vegetative functions, assimilation, growth, and reproduction, 

 surrounded by an envelope formed by the limbs, the sense- 

 organs, the nerves and the brain, which is the centre of 

 this "envelope." 1 Animals may differ from one another 

 enormously in the external parts, particularly in the appen- 

 dicular skeleton, without showing any great difference in 

 the plan and arrangement of their internal organs. 



1 iv., p. 3X5. - iv., pp. 3- 1 10 



:1 It has been revived in our oun clays by Bcrgson, M attire et 

 Miinoirc, p. 57. 

 4 iv., pp. 7-15- 



