234 LAMARCK, HIS LIFE AND WORK 



ences, "became preserved and were propagated by 

 generation.* 



" The bird ■which necessity {besoin) drives to the 

 water to find there the prey needed for its subsist- 

 ence separates the toes of its feet when it wishes to 

 strike the water f and move on its surface. The skin, 

 which unites these toes at their base, contracts in this 

 way the habit of extending itself. Thus in time the 

 broad membranes which connect the toes of ducks, 

 geese, etc., are formed in the way indicated. 



" But one accustomed to live perched on trees 

 has necessarily the end of' the toes lengthened and 

 shaped in another way. Its "claws are elongated, 

 sharpened, and are curved and bent so as to seize the 

 branches on which it so often rests. 



" Likewise we perceive that the shore bird, which 

 does not care to swim, but which, however, is obliged 

 {a besoin) to approach the water tp obtain its prey, 

 will be continually in danger of sinking in the mud, 

 but wishing to act so that its body shall not fall into 

 the liquid, it will contract the habit of extending and 

 lengthening its feet. Hence it will result in the gen- 

 erations of these birds which continue to live in this 

 manner, that the individuals will find themselves 

 raised as if on stilts, on long naked feet ; namely, 

 denuded of feathers up to and often above the 

 thighs. 



N^ '' I could here pass in review all the classes, all the 

 prders, all the genera and species of animals which 

 (sxist, and make it apparent that the conformation 

 of individuals and of their parts, their organs, their 



* Lamarck by the word gindration implies heredity. He nowhere 

 uses the word h&idM. 



\ ' ' L'oiseau que le besoin attire sur I'eau pour y troyver la proie 

 qui le fait vivre, ecarte les doigts de ses pieds lorsqu'il veut frapper 

 I'eau et se mouvoir 4 sa surfaee " ^p. 13). If the word veut has sug- 

 gested the doctrine of appetency its meaning has been pushed tog 

 far by the critics of Li(niarjk. - ' 



