The Inheritance of “Acquired” Characters

Abstract

I AM 10th to take part in barren controversy on this subject again, but I feel it is really necessary to say a few words in reply to the letter of “A. D. D.” in NATURE of February 13. When that gentleman refers to the slightly dogmatic tone of his original article he is not doing himself justice; the article was as dogmatic as it could possibly be. Now he asserts that there is no sense in the distinction between acquired characters and innate ones with regard to inheritance, that all characters are both acquired and innate. This in the accepted meaning of the words is simply untrue. If a man takes a summer holiday and becomes sunburnt, the colour of his skin is an acquired character; a negro's colour develops without exposure to the sun; he is brown (not black) when he is born; that is an innate character. The supernumerary toe in a Dorking fowl is an innate character; it is not acquired in the accepted sense of that word. Acquired characters are those changes in the individual which are due to a change of external conditions, i.e. of stimuli; innate characters are those which develop without any stimulus, except what Dr. Reid calls the stimulus of nutrition.