Il6 PIONEERS OF EVOLUTION. 



the volume of each living body and of all its parts 

 up to a limit determined by its own needs. 



2. New wants in animals give rise to new move- 

 ments which produce organs. 



3. The development of these organs is in propor- 

 tion to their employment. 



4. New developments are transmitted to off- 

 spring. 



The second and third propositions were illus- 

 trated by examples which have, with good reason, 

 provoked ridicule. Lamarck accounts for the long 

 neck of the girafife by that organ being continually 

 stretched out to reach the leaves at the tree-tops; 

 for the long tongue of the ant-eater or the wood- 

 pecker by these creatures protruding it to get at 

 food in channel or crevice; for the webbed feet of 

 aquatic animals by the outstretching of the mem- 

 branes between the toes in swimming; and for the 

 erect position of man by the constant efiforts of his 

 ape-like ancestors to keep upright. The legless con- 

 dition of the serpent which, in the legend of the Gar- 

 den of Eden, is accounted for on moral grounds, is 

 thus explained by Lamarck : " Snakes sprang from 

 reptiles with four extremities, but having taken up 

 the habit of moving along the earth and concealing 

 themselves among bushes, their bodies, owing to 

 repeated efiforts to elongate themselyes and to pass 

 through narrow spaces, have acquired a considerable 

 length out of all proportion to their width. Since 

 long feet would have been very useless, and short 



