LAMARCK. jgy 



In his earlier work this was first expressed b)- 

 Lamarck as follows: — 



" All that Nature has caused individuals to acquire or lose by 

 the influences of environment to which they have been long 

 exposed, and consequently by the influence of the predominant 

 employment of a certain organ, or by that of the continued lack 

 of use of the same part, — all this Nature conserves by generation 

 to the new individuals which arise, provided that these acquired 

 variations (changements) are common to both sexes, or to those 

 which have produced these new individuals." 



This law is now known as 'the inheritance of 

 acquired characters,' or better, to revive Lamarck's 

 original idea expressed in the word chaugcmoiis. 

 we should call it the theory of inlicriiaucc of 

 acquired changes or variations. 



This theory^ of Lamarck is seen to be substan- 

 tially similar to that of Erasmus Darwin, and to 

 depart widely from that of Buffon, for Lamarck 

 does not follow Buffon in supposing that environ- 

 ment directly produces changes in animals, either 

 in their form or organization. In a single sentence 



^Premiere loi. — La vie, par ses propres forces, tend continuellement \ 

 accroitre le volume de tout corps qui la possede, et h etendre les dimensions 

 de ses parties, jusqu'^. un terme qu'elle amene elle-meme. 



Deuxieme loi. — La production d'un nouvel organe dans un corps animal 

 resulte d'un nouveau besoin survenu qui continue de se faire sentir, ct d'un 

 nouveau mouvement que ce besoin fait naitre et entretient. 



Troisieme loi. — Le developpement des organes et leur force iraction sont 

 constamment en raison de I'emploi de ces organes. 



Quatrihne loi. — Tout ce qui a ete acquis, trace ou change dans I'organisa- 

 tion des individus, pendant le cours de leur vie, est conserve par la generation 

 et transmis aux nouveaux individus qui proviennent de ceux qui ont cprouve 

 ces changements. 



