168 Life and Letters of Francis Galton 



himself by calling it a " quasi-accordance with the theoretical law of Frequency 

 of Error." Personally I do not see why it is needful to show accordance, quasi 

 or otherwise, with the normal law of error. It might have served Galton's 

 purpose to show "tailing off" in his distributions of measurements. But it 

 does not seem to me that measurement or enumeration is really what he 

 needs, or it must be measurement or enumeration of characters which belong 

 alike to the various genera, not to a loop alone. The transitions from loop to 

 whorl are qualitative rather than quantitative, and it is the frequency of 

 these qualitative intermediates that we need to analyse. I am inclined to 

 think that this was later recognised by Galton, for I have several times heard 

 him say that there appeared to him nothing to be measured in finger-prints 

 in general; could I not suggest a measurable character? I still know of 

 nothing that will apply satisfactorily to all types, and I hold that scientific 

 finger-print classification must be qualitative*. 



As I have said, I do not see, even if Galton had proved that measurements 

 on loop finger-prints only followed the normal law of distribution, that it 

 would follow that types of finger-prints are genera. In order to prove this 

 we should need to measure characters which run through the whole series 

 of types and this is precisely what it does not appear feasible — at any rate for 

 the present — to achieve. Undoubtedly finger-print patterns do occasionally 

 blend, if such occasions are less frequent than the instances in which they 

 appear to be exclusive (see our Plates XIII and XIV, p. 181). It seems 

 therefore that the key to the matter lies in a closer study of the heredity 

 of finger-prints than has yet been made. With this Galton certainly would 

 have agreed. He writes (p. 21): 



"There is reason to believe that the patterns are hereditary. I have no adequate amount 

 of data, whereby to test the truth of this belief by a direct inquiry, but rest the belief partly 

 on analogy, but more especially on the ascertained existence of a considerable tendency to 

 symmetry. When, for instance, there is a primary pattern on one thumb, there are not far 

 from ten chances to one in favour of its being found on the other. Again, if there is a loop in 

 one thumb, there is a strong chance that it will be found in the other thumb also. Similarly 

 as regards each pair of corresponding fingers. Therefore the causes of the pattern must not be 

 looked for in purely local influences. Some of the causes why it and not another pattern is 

 present, are common to both sides of the body and may therefore be called constitutional, and be 

 expected to be hereditary." 



Galton continuing next states that finger-prints form an "instructive 

 instance of the effects of heredity under circumstances in which sexual 

 selection has been neutral." He seems to think that sight could be the only 

 sexual selective factor, for he says that finger-prints are too small to attract 

 attention. He remarks that they appear to be uncorrelated with any desirable 

 or repellent quality. Galton holds that they might possibly be related to 

 sensitivity, the average breadth of a ridge-interval being possibly a measure 

 of delicacy in the sense of touch f. But he states that this could have nothing 



* I write this fully aware of the attempts made by Kristine Bonnevie [Journal of Genetics, 

 Vol. xv, pp. 46-54) to give a common measurable characterisation to all types of finger-print 

 pattern. 



t Experiments on this point wore soon after made for Galton by Titchener, who found no 

 relation between ridge-interval and sensitivity. 



