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Personal Identi,Jication and Description   167

After a few remarks on scars, which consist chiefly in noting how few he had found which destroyed the patterns to any considerable extent, and how even in these cases with- "rolling" generally enough is left for sound identification (see our Plate VI, p. 154), Galton turns to another matter, which needs possibly' more criticism or at least an ampler treatment. He considers that there are certain main types of finger-prints, "arches," "loops," "whorls," etc. There are also, he admits, transitional forms which create difficulty in classification, but he says the result of statistical observation shows these intermediates to be relatively few. He considers therefore the finger-print types to be analogous to ordinary genera, and in order to illustrate this he takes the case of the loop, and (a) counts the number of ridges in AH (see our Fig. 21 (iii) and (iv), p. 163), (b) measures the index VY/OI, and (c) the index AO/A H. Using both hands, and populations numbering 140 to 176 individuals only, he forms six frequency distributions-, reducing them to percentages. For example:

Percentage Number of Ridges in 166 Right Thumb Loop Prints.

 
 

2

       

5

   

7

8

9

j

10 i 11

12 i 13

14

15 I above

i

 

1

2

 

2

2

 

3

4

 

8

8

11

(

I

9

14   11

10

7

6

 

2

Percentage Value of Index V Y/OI in 149 Left Thumb Loop Prints.

 

0.3-0.4 0.5-0.6 0.7-0.8 i 0.9-1.0

11   14   i   18

1.1-1.2 1.3-1.4 1.5-1.6 1.7-1.8 1.9-2.0

23   7   10   6   6

2.1-2.2

1

above

2

Galton does not apply an individual test for normality of distribution to these rather abnormal-looking distributions*, but reducing them to their medians and quartiles (see our Vol. if, pp. 385-6, 401) compounds them together to form a single average "ogive" curve (see our Plate II, p. 31). His final comparison is as follows

Ordinates of Ogive Curve from Six Distributions and the computed Values.

 

Six Distributions

Computed    

-231

-244

-182

-190

--117

-125

- 93 1

-100 I

I

- 73

- 78

- 37 + 1

- 38 1   0

I

+ 38

+ 38

+ 77

+ 78

+ 107

+ 100

+ 139

+125

+ 213

I +190

+ 260

+244

Grades    5 ( 10

20   25 I

30   40

50

60   70   75

80 i 90   95

Considering that we have 965 observations to start from, this does not appear on the face of it a very good agreement, and even Galton (p. 22) contents


He merely places his observed values alongside the normal curve results, and says that considering the paucity of observations "there is nothing in the results that contradicts the possibility of much closer conformity when many more observations are dealt with." (p. 19.)


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