Inheritance of Acquired Characters 227 



These laws are, Lamarck says, fundamental truths which 

 cannot be misunderstood except by those who have never 

 observed or followed nature in her operations. He insists 

 that it is a mistake to suppose that the parts are responsible 

 for the functions, for it is easy to demonstrate that it is the 

 needs and uses of the organs that have caused the parts to 

 develop. 



If it is supposed, he continues, that these laws are hypo- 

 thetical, they may be demonstrated by the following facts : 

 The adult baleen whale is without teeth, although in the 

 foetus teeth are present, concealed in the jaws. The loss 

 of the teeth is the result of the whale swallowing its food 

 without first masticating it. The ant-eater is also without 

 teeth, and has also the habit of swallowing its food without 

 chewing it. The mole has very small eyes, and this is the 

 result of its having made very little use of them, since its 

 habits are subterranean. Another animal, the aspalax, has 

 only the rudiments of eyes, and has almost completely lost 

 the power of sight. This animal also lives underground like 

 the mole. 



Proteus, an aquatic salamander living in deep caves, has 

 only rudimentary eyes. In these latter cases it is the disuse 

 of the eye that has led to its degeneration. This is proven, 

 Lamarck adds, by the fact that the organs of hearing are 

 never in this condition, because sound vibrations penetrate 

 everywhere, even into the densest bodies. 



It is a part of the plan of organization of the reptiles that 

 they have four legs ; but the snakes, although belonging to 

 this group, have no legs. This absence of legs is explained 

 by their having acquired the habit of gliding over the ground, 

 and of concealing themselves in the grass. Owing to their 

 repeated effort to elongate themselves, in order to pass 

 through narrow spaces, their bodies have become drawn out. 

 Under these circumstances legs would be useless, since long 

 ones would interfere with their motion, and short ones could 



