236 HARRIS HAWTHORNE WILDER. 



V. It follows, therefore, that the modifications of the original 

 typical patterns, as given in II. and III: above, must be affected 

 through modification of the germ-cells, which determine at each fer- 

 tilization the form of pattern for the new individual. These pat- 

 terns are often atavistic, that is, a primitive pattern may oc- 

 casionally appear, but in the main the progress has been a decided 

 one, so that the majority of men show a nearly complete efface- 

 ment of the original complicated condition. 



VI. In each given area the characteristic ridge direction of a 

 typical human hand is precisely that to which the ridges would be 

 pushed or pressed if considered plastic and capable of being acted 

 on directly by the objects which naturally come into contact with them 

 in the ordinary uses of the hands and feet. That is, the ridges are 

 everywhere arranged to run at right angles to the prevailing 

 direction along which contact objects would push or slip. In the 

 hand, which is constantly grasping cylindrical objects, such as 

 boughs, handles of instruments, ropes, and numberless similar 

 things, the ridges of the distal half of the palm tend to lie straight 

 across it, a position which, in the highest degree possible for man, 

 is expressed by the formula 1 1 9 7 5. It is thus significant that 

 in the right hands of all human races this formula is found in 22-25 

 per cent, of the cases, while in left hands this formula forms only 

 4 per cent, of the cases. 1 That the same percentages hold among 

 such diverse human races as Whites, Negroes, and Maya Indians 

 marks this as a natural human tendency, and suggests that this 

 result has been gained since the adoption of right-handedness. 



VII. Finally, (i) since the configuration of the friction-ridges 

 is directly heritable, probably in conformity to the laws of 

 Mendel; (2) since the countless elements involved in the ridge 

 arrangement are precisely similar to what would be produced in 



and it is not very likely, yet, until otherwise explained, their occurence prevents 

 the dogmatic assertion that no change can absolutely take place after the ridges 

 are first laid down. Concerning a modification of this sort after birth, this is 

 still less likely, and may be practically denied. The author is in possession of a 

 series of prints of the right forefinger of a child, beginning with the second year, 

 continued at approximately two-year intervals until the age of twelve, and 

 still being collected. In this there is an unusual number of these "suppressed" 

 ridges, yet in the interval covered by the series there has not been the slightest 

 change in any of them. 



1 Wilder, 1904, Amer. Anthrop., Vol. 6, p. 279. 



