Page:Popular Science Monthly Volume 62.djvu/53

Rh of the papillary ridges becomes of little importance. The influence of environment becomes entirely removed, and the only reason for the farther continuance of these parts is the conservative power of heredity, which may perpetuate, apparently for a vast period of time, characteristics no longer of necessity to the organism.

Briefly stated, the law described above is this: that only useful and important parts retain a certain normal form in the various individuals of a given species, and that, as they become of less importance, they tend more and more to vary individually, the range of variation increasing with time and the degree of uselessness, if such an expression may be allowed; conversely, an organ that is seen to possess marked individual variation is shown to be of secondary importance, and may be either a rudimentary organ, that is, one on the way towards a greater perfection in the future and in which the variations represent the numerous experiments or attempts to find the form best adapted for a special purpose, or, again, it may be a vestigial organ, or one in which its point of highest usefulness is passed and in which the variations represent various degrees of degeneracy, or stages in its gradual eradication from the organism.

Returning to the case under consideration, a brief mention should be made of another feature of the monkey palm or sole besides that of the patterns, and that is the low but evident mounds upon which the patterns are placed and which more properly represent the elevations or pads themselves. Although these have suffered more in the transition to the human form they are commonly not absent, even in the adult and may be seen with especial clearness in the embryo. In many adult hands the three palmar pads are clearly brought out by simply bending back the fingers and looking across the palmar region, and this notwithstanding the fact that the modern, rather ingenious 'science' of palmistry locates here four 'mounts' rather than three, and associates them with the fingers instead of with the intervals between them; an interesting illustration of what even the most careful observation will do without a rational basis.

The endless variety shown in the disposal of the epidermic ridges as outlined above will suggest several important lines of study, as, for example, the discovery of a system or of laws governing the variation; the possible influence of heredity upon the variation; and through this the possibility of the discovery of characters which may serve as criteria of race; the use of the markings in personal identification, and so on; and, although the simple scrutiny of a few palms may suffice for a preliminary examination, a need will soon be felt of some method by which a permanent and accurate record may be made, something in the form of a print or impression which may be available at all times