Heredity and Acquired Characters

Abstract

(1) MOST biologists believe that the heritage travels down the germ-tract. (2) All biologists believe that in the germ-cell are none of the characters which the individual afterwards develops, but only potentialities for producing them in response to fitting nurture. (3) It follows necessarily that only potentialities are transmitted. (4) All that is transmitted is not produced (as characters of the individual), for fitting nurture may be lacking. (5) Therefore, inheritance and reproduction are not synonymous terms. (6) The individual can produce nothing but what was potential in the germ-cell, and nothing except in response to fitting nurture. (7) Necessarily, therefore, all characters are innate, acquired, germinal, somatic, and inheritable in exactly the same sense and degree. Given these facts and inferences, I asked biologists why they described some characters as “innate,” “germinal,” and “inheritable,” and others as “acquired,” “somatic,” and “non-inheritable.” I gave the example of the head and the scar, both ancient products of evolution. Why, when the child is like his parent both by nature and by nurture, is he said to inherit the head but not the scar? Why is the word “inherit” used as synonymous with “vary,” its direct opposite, in the case of the scar? Really, I was asking for such definitions of biological terms as would accord with the current usage of them. As yet I have got none. I think I shall get none.