ANTHROPOMETRIC LABORATORIES 251 



at the Royal Institution (which was delivered May 

 25, 1888) on what is briefly called " Bertillonage " ; 

 that is, on the system devised by M. Alphonse 

 Bertillon for identifying persons by the measurements 

 of their bodily dimensions. The subject was attract- 

 ing much interest at the time, and had received a 

 & 



great deal of off-hand newspaper praise. There 

 was, however, a want of fulness in the published 

 accounts of it, while the principle upon which 

 extraordinarily large statistical claims to its quasi- 

 certainty had been founded was manifestly incorrect, 

 so further information was desirable. The incorrect- 

 ness lay in treating the measures of different dimen- 

 sions of the same person as if they were independent 

 variables, which they are not. For example, a tall 

 man is much more likely to have a long arm, foot, 

 or finder than a short one. The chances against 



o o 



mistake had been overrated enormously ow 7 ing to 

 this error ; still, the system was most ingenious and 

 very interesting. 



I made the acquaintance of M. Bertillon during 

 a short visit to Paris, and had the opportunity of 

 seeing his system at work. Nothing could exceed 

 the deftness of his assistants in measuring the 

 criminals ; their methods were prompt and accurate, 

 and all the accompanying arrangements excellently 

 organised. But I had not means of testing its 

 efficiency with closeness, which would have required 

 more time and interference with current work than 

 was permissible. I was nevertheless prepared to give 

 an account at the Royal Institution of what I had 

 seen, but, being desirous of introducing original work 

 of my own, I gave to my lecture the more general 



