68 THE GERM-PLASM THEORY 



new habits can scarcely be formed without some 

 change taking place in the bodily organization, 

 for they must give greater exercise to some parts 

 and less to others than the earlier habits. The 

 parts now more freely used, perhaps indeed now 

 used for the first time, will tend to become more 

 fully developed and will improve, whilst those 

 which have fallen into desuetude will tend to 

 atrophy and degenerate. To these theses there 

 will be little opposition. No one will deny that a 

 man's muscles may be enlarged and improved by 

 long-continued and well-regulated exercise. But 

 it is another thing to argue, as some do, that new 

 organs may arise in response to new needs. And 

 it is also another thing to admit that the improve- 

 ment in the old organs may be transmitted or 

 that the newly-acquired organs may be transmitted 

 to a younger generation. Lamarck died poor, 

 blind and little regarded by his contemporaries : 

 yet his influence is still strong, and the neo-Lam- 

 arckians are an important wing of the biological 

 army. A single example will explain the meaning 

 of Lamarck's views and the distinction between 

 them and the views of Darwin. The giraffe is pro- 

 vided with an extraordinarily long neck and very 

 tall forelegs. These he acquired, according to the 

 Lamarckian view, by constantly stretching after 

 the foliage of trees, on which he feeds, and by 

 ever reaching after higher and yet higher boughs. 

 According to the Darwinian view certain giraffes 

 were by reason of causes inherent in the embryo 

 provided with somewhat longer necks than their 

 fellows. In time of stress these giraffes could get 



