356 APPENDIX A 



But when we speak of the inborn or the acquired characters 

 of an individual, then our use of the terms, however much 

 sanctioned by custom, is clearly inaccurate, and has, in fact, 

 been productive of endless confusion. Here, by inborn characters 

 we usually imply those characters which have been developed 

 under the stimulus of nutrition, and by acquired those characters 

 which have been developed under the stimulus of use or injury. 

 But it is difficult to understand how characters developed under 

 one form of stimulus can be more inborn than those developed 

 under another. The individual develops under each only because 

 a prolonged course of ancestral evolution has evolved in his race 

 the capacity to so develop. The capacity to react to the stimulus 

 of use or injury, results just as much from the constitution 

 of his germ-plasm, as the capacity to respond to the influence of 

 nutrition. Moreover, the growth which results from use is, apart 

 from the stimulus, of exactly the same nature as that which 

 results from the stimulus of nutrition ; thus when inspecting a 

 man's limb we cannot separate the two. The confusion which 

 results from this illegitimate use of terms is well demonstrated 

 by such a case as the following. Imagine identical twins in 

 utero ; suppose that one receives more than his fair share of 

 nutriment, and consequently develops better than the other. 

 Then clearly the two will differ by acquirement, but it would 

 puzzle us to indicate which twin has made the differentiating 

 acquirement. 



Logically, therefore, all characters are acquirements. More- 

 over, all characters are equally inherited, or rather not inherited, 

 for given similar stimulus a man's child develops his "acquire- 

 ments " just as certainly as his " inborn " characters. The term 

 inherited, like the term inborn, is, in fact, used by biologists, 

 consciously or unconsciously, in a metaphorical sense. When we 

 say that a child has inherited his father's nose, we do not mean 

 that the organ has been transferred to the child, leaving the 

 parent derelict. We mean merely that their germ-plasms were 

 similar, and that their characters have developed under similar 

 stimuli. But in this sense a child inherits a scar on its parent's 

 nose ; for, given the fit stimulus, a cut, the scar develops just as 

 inevitably as the nose. When people speak of the inheritance 

 of an acquirement, they imply no more than that a character, 

 which use or injury developed in the parent, has appeared in 

 the child under the quite different stimulus of nutrition. When 

 we remember that the capacity to develop a given character 

 under a given stimulus is an adaptation which has been slowly 

 evolved in the race under stringent selection, we are able to 

 realize the miraculous nature of the phenomenon that is sup- 

 posed to occur. In a single generation a character is thought 

 to be transferred from one category to another. Thus suppose 

 a child is said to inherit a scar ; then the parent makes the 



