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188   Life and Letters of Francis Galton

measured fall into classes in which there are 7 to 24 repetitions*. But even the group of 24 indiyiduals could be separated out by taking finer divisions of the head measurements than the three classes and introducing seven eye.colour classes. I think Galton was not unnaturally critical of bertillonage, because it started by theoretically asserting. the independence of measurements ,which he knew to be correlatedt; it did in fact overlook one of his greatest discoveries, the quantitative measurement of the correlation of bodily measurements.' Nevertheless Galton is fair to the results of the system:

" It would appear from these and other data, that a purely anthropometric classification, irrespective of bodily marks and photographs, would enable an expert to deal with registers of considerable size ... it seems probable that with comparatively few exceptions, at least two

thousand adults of the same sex might be individualised, merely by means of twelve careful measures, on the Bertillon system, making reasonable allowances for that small change of proportions that occurs after a lapse of a few years, and for inaccuracies of measurement. This estimate may be far below the truth, but more cannot be safely inferred from the above very

limited experiment." (p. 163.)

It may be remarked that Bertillon does not appear to have made even such a limited experiment before he started his vast collection on the basis of his "independence" dogma!

Some account is then given of an American system of identification in the case of recruits and deserters. It seems to be based on height, age (how judged?), hair and eye colours for indexing purposes and then on a careful record of the body-marks placed on outline figures. Body-marks form of course an important factor of bertillonage (pp. 164-5). Galton remarks that no system he knows of appears to take account of the teeth. If teeth are absent when a man is first examined, they will be absent when he is examined a second time. He 'may have lost others in addition, but the fact of his having lost certain specified teeth prevents his being mistaken for a man who still possesses them (p. 166).

M. Herbette, speaking at the International Prison Congress in Rome, remarked of bertillonage

" In one word, to fix the human personality, to give to each human being an identity, an individuality which can be depended upon with certainty, lasting, unchangeable, always recognisable and easily adduced, this appears to be in the largest sense the aim of the new method.",

Galton fitly remarks that these perspicacious words are even more applicable to the method of finger-prints than to that of anthropometry. Bertillonage can rarely supply more than grounds for very strong suspicion, finger-prints alone are amply sufficient to produce absolute conviction of identity.

 

Number of Repetitions

     

10

11

14

19

24

Number of Individuals

28

1   8

18

20

22

28

19

24

t Some of the Bertillon measurements are indeed highly correlated. See Macdonell, Biometrika, Vol. 4 pp 202, 212.


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