342 



NA TURE 



[February 13, it 



LETTERS TO THE EDITOR. 



[The Editor does not hold himself responsible for opinions 

 expressed by his correspondents. Neither can he tindertahe 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Nature. 

 .\o notice is taken of anonymous commimications.} 



The Inheritance of "Acquired" Characters. 

 Dr. Bastian is unaccountably mistaken. Nothing in my 

 letter indicates that I " assume (in the face of multi- 

 tudinous difficulties) that the germ cells of all human 

 beings are potentially alike." 1 have no doubt that germ 

 cells differ, and therefore that the individuals which arise 

 from them would vary even were' they reared under abso- 

 lutely identical conditions. These germinal differences 

 between individuals and species are rightly termed innate. 

 Individuals differ also because they are exposed to unlike 

 influences during development. These differences, due to 

 the unequal play of stimuli, are rightly termed acquired. 

 But in my letter I did not allude to differences between 

 individuals, nor even to acquired differences between one 

 side of the body and the other. I merely discussed the 

 question whether the terms " innate " and " acquired " 

 correctly distinguished between certain classes of 

 characters. I gave reasons for believing that a nose is 

 no more innate and inheritable than a scar on it. If Dr. 

 Bastian thinks I am in error, will he indicate in what 

 sense the scar is less inborn and more acquired than the 

 nose ? 



Often we are able to express our meanings very well by 

 inaccurate terms the use of which has been sanctioned by 

 convention. If, then, by " innate " and " inheritable " we 

 merely imply characters which arise under the stimulus of 

 nutriment no great harm is done. But, unfortunately, the 

 words are usually given their literal meanings. The nose 

 is supposed to be more rooted in the germ-plasm, more a 

 product of evolution, more truly inborn than the scar; 

 use acquirements are treated as trivial accidents unworthy 

 the attention of the student of evolution ; as a result, a 

 very important phase of evolution is obscured and the 

 study of it neglected. Dr. Bastian treats as absurd the 

 belief that the bulk of human development after birth is 

 an "acquirement." But, suppose we supplied an infant 

 with sufficient nutriment but denied its body the stimulus 

 of use and its mind the stimulus of experience, what sort 

 of physical and mental maturity would the individual 

 achieve ? Would he develop nearly as well as the foetus 

 in the uterus or the butterfly in the chrysalis? How many 

 of his physical and mental parts would attain even the 

 stage of development reached in a little child? Apart, 

 however, from the precise degree in which the human 

 being develops under the influence of use and experience, 

 the points I wish to urge are : — (i) that a principal phase 

 of the evolution of the higher animals is the evolution of 

 a power of responding by growth to these stimuli ; {2) that 

 the characters which thus arise are in some species (e.g. 

 man) of great magnitude ; and (3) that they are just as 

 much a part of " normal " development as the inborn 

 traits. Variation renders a species adaptable. But the 

 power of developing under the stimulus of experience 

 confers adaptability on the individual as well. In his very 

 interesting letter, Mr. A. Bacot refers to the " repertoire " 

 patterns of " the peppered moth " (Nature, January 30). 

 Consider how many repertoire patterns are possessed by 

 the human being, whom the environment may train to 

 play the part of an acrobat or a clerk, a beggar or a 

 king. 



Dr. Bastian insists that " post-natal growth is essenti- 

 ally due to the same causes as pre-natal growth." His 

 words sound well, but what do they imply in this connec- 

 tion — that use plays nearly as important a part in pre- 

 natal as in post-natal development? 



He declares that the memories of Chinese and 

 Mohammedan children are exceptionally good, and accounts 

 for this circumstance by the hypothesis that the memory 

 (the faculty of learning as distinguished from the things 

 that are learht which are only the contents of the memory) 

 grows in the individual with use, and that this acquire- 

 ment is transmitted. Animals which are not protected and 

 trained by their parents have little or no memory. It 



NO. 1998, VOL. f'j'] 



would be of small use to them, for they must begin life 

 fully equipped for the struggle by instinct. But in pro- 

 portion as they are protected and trained, they are mentallv 

 immature on entrance into the world. The function of 

 parental protection is to afford time and opportunity to 

 make the acquirements without which they cannot attain 

 maturity, and which in them in some measure take thr 

 place of instincts. The helplessness of the human beint; 

 at birth, and the prolonged training necessary before he is 

 able to maintain independent existence, is connected with 

 the magnitude of his memory and the acquirements he 

 makes by means of it. Now what is the evidence that 

 memory (the faculty, not the contents) grows with use? 

 So far as I am able to judge, memory, like the homologous 

 power of growing physically, is greatest just when it is 

 most useful — in the little child who has to equip himself 

 with absolutely essential acquirements, and who, starting 

 from a position of blank ignorance and incapacity, in a 

 few months reduces the chaos of his world to order, and 

 within two years even learns to walk and speak a language, 

 as well as a vast deal more. Has Dr. Bastian any 

 evidence that Chinese and Mohammedan adults are abb 

 to learn chapters of the Bible and the Koran more readily 

 than their children? If, then, as seems probable, memor> 

 does not grow with use, how can the transmission of 

 acquirements cause an increase of this faculty in a race? 

 Southsea, February 9. G. .Arciidall Reid. 



Mr. B.«ot's interesting letter (p. 294) on melanism in 

 nioths suggests that the moth I had seen in Yorkshire 

 (though I knew it appeared elsewhere) has a " repertoire " 

 of colours as an actor has a repertoire of plays, and each 

 moth in his time plays many parts. But the actor learnt 

 them all, and the moth apparently inherits them all, the 

 result being the same, since each possesses them all, and 

 according to environment each appears occasionally " in 

 yellow stockings and cross-gartered," or " in customary 

 suits of solemn black," so that while the actor's know- 

 ledge of Hamlet dies with him, the moth's repertoire is 

 perpetuated by an ineradicable involution. The question 

 that lies behind all this does not seem to be answered by 

 reference to the operation of evolution in a " previous 

 epoch," for evolution begs the question. If we say that 

 evolution in the past packed the " germ plasm " with 

 possibilities, and evolution in the present only unpacks 

 here and there one as it is required, we seem to be illogical 

 in the use of any argument founded upon such an un- 

 certain term, for the evolution of an actor and the evolu- 

 tion of a moth are two totally and impossibly different 

 things, yet the stimulus of environment produces the sani'- 

 results. 



If we believe that the racial moth has plastic possibili- 

 ties he may start with whatever form or colour you like, 

 and he will, when it is good for him, become " peppered," 

 and will continue peppered until it is bad for him, when 

 he will become black or otherwise. But if he has to carry 

 a whole load of inherent characters all the time, where, 

 when, and how did his germ plasm "acquire" them? 

 Is what was possible in the past impossible now? And, 

 further, does not the geological statute of limitations 

 forbid the possibility of " cramming " every plant and 

 animal with all these inherent characters during the short 

 time that most species exist? 



Dr. Archdall Reid in his most thoughtful letter sends 

 a breath of delightfully fresh air into the subject, for hf- 

 suggests that, after ail, the arguments on both sides of 

 this fascinating subject are not about facts, but words, 

 and suggests (p. 293) that " confusion, misunderstanding, 

 and futile controversy " are due in this matter to the " use 

 of inaccurate terms." The idea of his letter suggests the 

 possibility of a complete explanation of this puzzling 

 question. 



If natural selection operated in the past by the slow 

 development of racial possibilities until a fixed type was 

 reached, and if " recapitulation " is established, tho 

 " adult " form at any stage short of the last must havf 

 had, like the imperfect individual, the power of somehow 

 acquiring characters that it then passed on to its de- 

 scendants ; and if this be so it is difficult to believe that 

 acquired characters are no longer transmitted, for in thar 



