Heredity and Biological Terms

Abstract

IT seems to me that the arguments of Sir Archdall Reid (NATURE, February 3, p. 726) and Sir Bryan Donkin (February 10, p. 758) leave the question of the meaning and use of the term “acquired characters” very much where it was before. Sir Bryan Donkin asks whether it may not be justly argued that if a child has a hand like its parent there is no change in “nature” or “nurture”; that if the child has a sixth digit which the parent had not there is a change in nature or heritage, but none in nurture; and that if the child has a scar there is no change in heritage, but only one in nurture. But I fail to perceive anything new in this or any difference from the usual conceptions which are general among biologists. It is a mere matter of terms and synonyms. The modern biologist would say that the normal hand was hereditary, or innate, or due to certain factors or genes in the chromosomes which usually are handed on unchanged “down the germ-tract”; that the sixth digit was a mutation, due to some change in the genes in the chromosomes, and therefore gametogenic; and that the scar was due to an injury which resulted in regenerative processes producing new tissue. Sir Bryan Donkin states that the scar is an “acquired difference,” but in terms of the germ-plasm the hand and the scar indicate no change. What, then, is the objection to terming the scar an “acquired character”? Every biologist would agree that it does not indicate a change in the chromosomes. Its possible subsequent ettect on heredity is expressly excluded from the discussion.