1 84 



HEREDITY AND EUGENICS 



systems. These details are clearly not inherited, 

 for no two patterns are alike in these particulars, 

 and Galton concluded that the chance of two finger 

 prints being identical was less than i in 64,000,000,000. 

 The inheritance of finger-print patterns is the 

 subject of a paper by Miss Elderton (1920). The 

 arch, loop, whorl, and composite are the types of 

 pattern used for criminal classification. But this is 

 inadequate for scientific distinctions. Galton in- 

 creased his four or five original categories up to fifty- 

 three. He was led to assume continuity between 



Fig. 32. — Twins, Eighteen Years of Age, from York, 



Pennsylvania. 



types, and for years sought quantitative measures 

 for the finger print. Miss Elderton adopts the follow- 

 ing order, arch, small loop, large loop, composite, 

 whorl, as a natural order in passing from type to type. 

 An effort was made to state the inheritance in 

 Mendelian terms. The difficulties were (i) in the 

 presence of transitional forms; (2) there is probable 

 inheritance of pattern with change of finger. As- 

 suming that inheritance was on the same finger from 

 parent to offspring, and classifying Galton 's data, she 

 found that : (i) Arch x arch and arch x composite ap- 

 pear to give no whorls ; (2) whorl x whorl and whorl 



