Characterisation, especially by Letters 505 



42, Rutland Gate, S.W. July 1, 1898. 



Dear George Darwin, Your small son has, I hear, a faculty about which I have been par- 

 ticularly interested in another child, namely the aptitude of identifying the perforated discs used 

 for musical boxes. I wish you would talk it over with your wife, and perhaps make a few experi- 

 ments and tell me the result on Wednesday. The experiments I mean, are 

 by taking the pile of discs and pulling out one of them very gradually from 

 among the pile until he recognises it. 



Does he know them with equal ease, face upwards or face downwards? 

 How many does he distinguish? At what age did he begin to do so? Am 

 I right (do you think) in supposing that it is a similar act of memory to that 

 of recollecting a hieroglyph or a scroll pattern, or the like, or is there any 

 possibility of suggesting the tune, in the distribution of the holes? I should be very glad of 

 some verbal information about this, as the case I have heard of in Northumberland seems to be 

 a very curious one, hard to explain except on the hypothesis of a portentous memory of patterns. 

 Do you think that you yourself could easily recollect and distinguish the discs? Can the other 

 children? Ever yours, Francis Galton. 



42, Rutland Gate, S.W. November 16, 1898. 

 Dear Professor Karl Pearson, Possibly you may intend going to the Royal Society 

 "at home" on Thursday (to-morrow). If so, or otherwise, will you dine as my guest at the 

 Philosophical Club? It is not necessary or even usual to dress. It would, I thought, have 

 been possibly a breach of etiquette, had I written, as soon as I knew it was settled, to congratu- 

 late you heartily on the forthcoming award of the Darwin Medal of the Royal Society. It 

 seems in every way most appropriate. I am delighted at the wisdom of the choice. 



Very sincerely yours, Francis Galton. 

 The enclosed card will give needful particulars as to the Phil. Club. 



7, Well Road, Hampstead, N.W. November 30, 1898. 

 My dear Mr Galton, I quite realise the difficulty about the term Reproductive Selection, 

 but I sought in vain three years ago for a better, and failing to find one have used it ever since 

 in my papers. I think also that it has something, not very much perhaps, in its favour. Evolution 



takes place by taking out of the community A, B, C, D, E, F, X, Y, Z, certain members 



L, M, X, and putting them into a position of advantage for propagating their kind. Anything 

 which contributes to this advantage is selection, a differential death-rate is Darwin's natural 

 selection, it should be Selection of the Fitter as all selection in wild life is "natural." Selection 

 by a differential birth-rate is my reproductive selection; it is selection of the most fertile. 

 There is a third kind — selection by a differential pairing rate, individuals L, M and N pair, or 



on the whole pair, more frequently than A, B, C, This is also a possible progressive source 



of change. It can be demonstrated to exist in civilised man, I am uncertain whether it is 

 actual as well as potential in wild life. All these three kinds of selection are factors in potentia 

 of evolution, but the last two involve no destruction. A uniform, non-differential death-rate 

 will still cause progressive change. Thus a selection of Celtic over Teutonic elements in 

 a population might arise without any survival of the fitter, if (i) the Celts married equally 

 frequently with the Teutons, but were more prolific, or (ii) if the Celts and Teutons were 

 equally prolific, but the Teutons married less frequently than the Celts. In both cases we 

 might speak of selection. In the former case we have selection by differential fertility, in the 

 latter case by frequency of pairing. In both, to be effective, the fertility must be inherited or 

 the relative tendency to pair, inherited. The former is what I term Reproductive Selection, the 

 latter is — what? Please send me a name for it, before I find it absolutely needful to coin one. 



Yours always sincerely, Karl Pearson. 



42, Rutland Gate, S.W. November 30, 1898. 

 My dear Professor K. Pearson, It is not so much the word " Selection " that seems to 

 be a stumbling block, as A'eproductire. I did my best to think it out, owing to the fact that 

 the Royal Society paper was sent to me as one of the Referees, and it was a duty to do so. 

 What I then wrote was somewhat to this effect: (1) The termination of the adjective should 

 accord with natural, artificial, sexual, and therefore be "-al," or its equivalent "-ic," for 



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