2 Mr. F. Galton on the Patterns in Thumb and Finger Marks.
in the library of the College of Surgeons), and subsequently adopted by other writers, with more or less variation, was not based on a sufficiently good foundation.
Since then I have steadily pursued the inquiry and found its interests to widen considerably as I proceeded. They led in many directions, and among others to the topic that will be the last discussed.
[italics]Data.[end italics]
The data on which this memoir is based are:--
(1.) The impressions of the two thumbs of about 2500 persons made for me, at my Anthropometric Laboratory, together with several impressions of the fingers.
(2.) A small and unique collection of impressions put at my disposal by Sir W.J. HERSCHEL, of which one half were taken many years ago, and the other half were taken quite recently from the same persons. I will speak of these more at length when the time comes for using them.
As regards the first set:--
I chose the two thumbs rather than two adjacent fingers on the same had, in order to obtain data respecting symmetry, on which however very little will be said here, and I chose a thumb of each hand, rather than a finger of each hand, because the thumb being greater than that of the finger the width of it affords a proportionately larger field for variety of patter. However, all that will be said about thumb marks, applies with but little reservation to finger marks, but with much more reservation to those of the toe.
I have myself not studied the latter, but PURKIN[acute accent over 'J']E states that the patterns of the toes are always of that particular sort which I shall define later on, and call a loop.
Origin of the Ridges.
I do not attempt to discuss the origin of the papillary ridges, because my knowledge is entirely second hand, and it would be presumptuous in me to do so. It will be sufficient to say that KOLLMAN'S (A. KOLLMANN, 'Der Tastapparat der Hand.' Hamburg and Leipzig, LEOPOLD VOSS, 1883) dissections seem to prove (see his figs. 19, 20):--
(1.) That each of the papillae(which lie below the cuticle) has two heads, which I will symbolize by the fork in the printed capital letter Y.
(2.) That the duct of the sudorific glands in passing outwards between the papillae, is bound up, as in a bundle, with the adjacent head of each of two neighbouring papillae. So that if the sudorific duct is symbolized by the printed letter I, a section across the ridges might be symbolized by a row of the letters Y and I printed alternately, thus-YIYIYIY. Then the union of the I with the adjacent prongs of two Y's forms the foundations of a ridge, and the clefts between the heads of the Y's correspond to the furrows.
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