These ridges and their peculiar disposal are an inheritance to us from our arboreal ancestors, and appear to be formed in the oldest primates by the coalescence of single units which arrange themselves in rows.[1] Whether or not this phylogenetic or racial stage is now passed through in each human embryo in accordance with the law of biogenesis has not as yet been shown, but it is certain that the ridges are seen fully formed and in their adult condition in a four-months' embryo, and that no change can afterwards take place in any detail.
As these surfaces are thus individually variant and as their condition is absolutely permanent throughout life, they offer the best possible criteria for a system of individual records, especially since they may be so easily recorded by means of printed impressions. All these points have been shown in a practical way by Mr. Galton, who has taken as the basis of his system the markings that cover the balls of the fingers, his 'finger-tips.' The present paper considers the remainder of the ridged surfaces and is thus seen to be an extension of the Galtonian system to a new territory. Whether ultimately the universal personal records, which will surely become a necessity in the near future, will be based upon a part or the whole of these surfaces is of no real moment and it is with the idea of being of genuine assistance to Mr. Galton and without any attempt at rivalry that I offer in the following pages a method of recording identity by means of palms and soles.
M. Bertillon has said that there are not lacking individually variant parts of the body capable of use for purposes of identification, but that what is needed is some system of recording and classifying these differences, so that an individual case can be easily found. The system proposed here will, I think, fulfil this demand, and it will be seen that each human being is as well marked and labeled as though he were tattooed with an individual name and number, the interpretation and manner of cataloguing these devices being the only part not furnished by nature.
The method of printing a palm or sole is a very simple one, and although there are many little details which will occur to one who does much of this work, the essentials are the same in all cases. The outfit for printing consists of a tube of mimeograph ink, a rubber roller such as is used in amateur photography, and unruled paper of the required size. An inking surface is prepared by pinning a sheet of paper to a
- ↑ This and other morphological points of which I shall make use in this article are from an unpublished paper upon the morphology of the subject, by an associate in my department, Miss Inez L. Whipple. At my suggestion Miss Whipple has undertaken the comparison of the human conditions of palm and sole with those of the lower primates and other mammals, and has studied also the ontogenetic development of the parts in man and other forms. This work, which is of great value in the present connection, will be published in full in a short time.
