Personal Identification and Description 



181 



memoir (see our p. 164). Unfortunately he uses the letter j throughout 

 his Plate 1 1 (our Fig. 32) for what he terms u in the text. 



"The divergent ridges that bound any simple pattern admit of nine, and only nine, distinct 

 variations in the first part of their course. The bounding ridge that has attained the summit 

 of any such pattern must have arrived either from the Inner plot (/) [radial delta], the Outer 

 plot [ulnar delta], or from both. Similarly as regards the bounding ridge that lies at the 

 lowest point of the pattern. Any one of the three former events may occur in connection with 

 any of the three latter events, so that they afford in all 3x3, or nine possible combinations. 

 It is convenient to distinguish them by easily intelligible symbols. Thus, let i signify a 

 bounding line which starts from the point 7, whether it proceeds to the summit or to the base 

 of the pattern; let o be a line that similarly proceeds from 0, and let j be a line that unites 

 the two plots [deltas] I and either by summit or by base. Again let two symbols be used, 

 of which the first shall always refer to the summit, and the second to the base of the pattern. 

 Then the nine possible cases are jj, ji, jo; ij, ii, io; oj, oi, oo. The case of the arches is peculiar, 

 but they may be fairly classed under the symbol jj." Finger Prints, pp. 80-81, with j as in 

 figure replacing u of Galton's own text. 



Galton next refers to measurements on the print and states that the 

 average ridge interval should be taken as unit of measurement for comparative 





Fig. 33. Illustrations of Ambiguities in minutiae, a may appear as b or c, d as e or/. 



purposes, especially where prints of non-adults are concerned. Plate 



11 



(our Fig. 33) gives illustrations of ambiguities in minutiae to which we have 

 previously referred (see our p. 165). 



Chapter VI (pp. 89-99) deals with Persistence. It is an extension of the 

 evidence partially given in the Phil. Trans, memoir (see our p. 166 and 

 Plates VII and VIII). Galton has here studied between twenty and thirty 

 different digits and compared minutiae to the number of 700 (p. 96) and 

 only found the one discrepancy to which reference has already been made 

 (see last lines on our p. 166). We reproduce Galton's Plates 13 and 14 (our 

 Plates XVI and XVII) as an illustration of his methods of comparing 

 minutiae, and of the periods for which persistency was demonstrated. Galton 

 again emphasises that it is in the minutiae, not in the measurements of the 

 pattern, that persistency lies (p. 98). After indicating that for the four periods 

 of life there is no change, and that we may expect in 700 minutiae only one 

 to fail us, Galton continues : 



"Neither can there be any change after death, up to the time when the skin perishes through 

 decomposition ; for example, the marks on the fingers of many Egyptian mummies, and on the 

 paws of stuffed monkeys, still remain legible. Very good evidence and careful inquiry is thus 

 seen to justify the popular idea of the persistence of finger markings, that has hitherto been too 

 rashly jumped at, and which wrongly ascribed the persistence to the general appearance of the 

 pattern, rather than to the minutiae it contains. There appear to be no external bodily 

 characteristics, other than deep scars and tattoo marks, comparable in their persistence to these 



