THE ;UTILITY OF USE- ACQUIREMENTS 71 



parent under the stimulus of use were ' inherited ' by the child 

 (i.e. were developed in the latter under the stimulus of nutriment), 

 a great part of its utility would be lost, for the character would 

 then develop, not in proportion to the needs of the individual, but, 

 within limits, in proportion to the supply of nutriment. The 

 alleged power of transferring characters due to injury and use from 

 their own category to another, therefore, is clearly not an adapta- 

 tion. If it exists at all it must have been evolved, not through 

 Natural Selection, but through miracle through a miracle which 

 was designed, not to benefit but to injure the species. 



113. Formerly, as noted already, the magnitude of the use- 

 acquirements made by the higher animals was not realized by 

 biologists. Indeed it is very seldom realized even now. The 

 study of them is still the most neglected department of biology. 

 In fact only exceptional acquirements were and are regarded as 

 acquirements. Ordinary acquirements, those made by every 

 normal individual who reaches maturity, were thought to be inborn 

 traits. For instance, the truth that almost the whole growth of the 

 infant's limbs after birth is due to use was undreamed of. This 

 failure to realize the magnitude and importance of the use-acquire- 

 ments has led to a failure to note the evolution of the c inborn ' 

 power of making them. The use-acquirement was regarded, not as 

 an adaptation, a product of evolution, but as a kind of. accident 

 which might befall any structure, and which, being transmitted, 

 might result in the evolution of inborn characters. Its magnitude 

 was tacitly assumed to be so small that the great part it plays in 

 co-adapting, in correlating, the parts of the individual, and otherwise 

 fitting him to the environment was not thought of. On the other 

 hand it was believed that the transmission of use-acquirements 



are compelled to assume, therefore, in accordance with the facts as far as observed, 

 at this non-adaptive kind of correlation is very rare rare, that is, as compared 

 the total number of the characters of the normal individual. Second, there is 

 at kind of correlation which results directly from Natural Selection, and which 

 ures the proportionate development of those characters which develop under 

 e stimulus of nutrition. For example, a large infant has usually, not only a large 

 y, but, correlated with it, proportionately large limbs and head. Third, 

 ere is that kind of correlation which results from the proportionate development 

 associated structures under the strain of use. Since this kind of. correlation 

 superimposed on and perfects the correlation of parts which have developed 

 under the stimulus of nutrition, it is usually the closest of all. Thus the correlation 

 in size between the muscles of the human adult arm is obviously closer than that 

 between ear and head. Correlation in the second and third instances is only 

 another name for co-adaptation, and evidence is hardly needed to establish 

 the fact that living beings tend to have their parts so adjusted as to render them 

 capable of existence. 





