156 CHARLES MIDLO AND HAROLD CUMMINS 



ably adequate, and when that number is reduced to seventeen, 

 as it is in the instance of comparisons in pattern intensity of 

 finger tips, it is hardly surprising that evidence .of correlation 

 between pattern intensity and functional sidedness was not 

 obtained. 



DISCUSSION 

 THE CONDITIONING OF SPECIFIC CONFIGURATIONS 



The basis of correlation between pads and dermatoglyphics 

 has been variously interpreted. The divergent conclusions of 

 different workers may be presented briefly. 



One view is that supported by Whipple and by Wilder. 

 Holding that the primary function of epidermal ridges is to 

 prevent slipping in walking or in prehension, these writers 

 claim that ridges are aligned at right angles to the force which 

 tends to produce slipping (or to the resultant of such forces). 

 Quoting from Whipple, "The shape of the pad elevation, the 

 direction of flexion, and the direction of motion, are the 

 factors determining the direction of the slipping force, and 

 therefore the direction of ridges." It will be apparent that 

 this interpretation implies the operation of Lamarckian fac- 

 tors, as does that of Kidd, who lays emphasis on the service 

 of ridges and their pattern arrangements in rendering the 

 tactile sense more acute. Schlaginhaufen, without committing 

 himself to the evolutionary mechanism accounting for pattern 

 formations, points out that patterns provide for more refined 

 tactile discriminations than do open fields. 



A third view, in contrast to interpretations which make func- 

 tional utility the agency of determining the character of the 

 ridge configurations, emphasizes developmental mechanics. 

 This position is implicit in the statement of Hepburn that a 

 pattern "has its character determined by the position, shape 

 and dimensions of the particular eminence [on which it lies] ". 

 He does not elucidate how these factors would influence the 

 pattern. Kollmann advanced the suggestion that ridge direc- 

 tion is determined by stresses incident to growth of the part. 



