344 STUDIES, SCIENTIFIC AND SOCIAL chap, xvi 



an advantage over other species in the general struggle 

 for existence. 



Even more removed from possible development through 

 use are the special organs of sense, such as the eye and 

 the ear. The complexity of structure in the internal ear 

 is amazing, with its spiral and semi-circular canals and 

 tubes, its membranes, ducts, and cartilages, its extra- 

 ordinary stirrup, hammer, and anvil bones, its wonderful 

 rods, hair-cells, and otoliths. It seems like some strange 

 machine, the connection of whose various parts and their 

 mode of action it is impossible to follow. Yet we feel sure 

 that every detail has its use ; and we have here an organ 

 the co-adaptation of whose several constituent parts is 

 essential to its utility, and is apparently more difficult to 

 bring about by variation and selection than in the cases 

 where Mr. Spencer thinks it absolutely necessary to call 

 in the aid of use-inheritance. But in this case it is utterly 

 unimaginable that any amount of air-waves impinging on 

 the tympanum can have tended directly to the production 

 of this highly complex and delicately adjusted organ. The 

 case of the ear alone appears to me sufficient to prove that 

 use-inheritance is not required for the development and 

 progressive modification of the most complex and beauti- 

 fully adjusted structures. 



We thus see that there is a wide range of characters 

 and structures, often involving the most beautiful adapta- 

 tions, in which use-inheritance can admittedly have no 

 share ; that even if it exists in other cases it is unnecessary, 

 since it can only give a little help in a process which 

 is demonstrably within the power of variation and natural 

 selection; and that the strongest arguments that have 

 been urged, either to show its supposed necessity or to 

 prove its actual existence, break down on close examina- 

 tion, and in some cases even affi)rd strong evidence against 

 it. Our conclusion, therefore, is, that no case has yet 

 been made out for the inheritance of individually acquired 

 characters, and that variation and natural selection are 

 fully adequate to account for those various modifications 

 of organisms which have been supposed to be beyond 

 their power. 



