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OCR Rendition - approximate
8 6 FINGER PRINTS CHAP. especially on the last phalanx of each finger. Some general account of them is always to be found in every manual of physiology and anatomy, but in an organ of such importance as the human hand, used as it is for very varied movements, and especially serviceable to the sense of touch, no research, however minute, can fail in yielding some gratifying addition to our knowledge of that organ. After numberless observations, I have thus far met with nine principal varieties of curvature according to which the tactile furrows are disposed upon the inner surface of the last phalanx of the fingers. I will describe them concisely, and refer to the diagrams for further explanation (see Plate 12, Fig. 19). 1. Transverse flexures. The minute furrows starting from the bend of the joint, run from one side of the phalanx to the other ; at first transversely in nearly straight lines, then by degrees they become more and more curved towards the middle, until at last they are bent into arches that are almost concentric with the circumference of the finger. 2. Central Longitudinal Stria. This configuration is nearly the same as in 1, the only difference being that a perpendicular stria is enclosed within the transverse furrows, as if it were a nucleus. 3. Oblique Stria. A solitary line runs from one or other of the two sides of the finger, passing obliquely between the transverse curves in 1, and ending near the middle. 4. Oblique Sinus. If this oblique line recurves towards the side from which it started, and is accompanied by several others, all recurved in the same way, the result is an oblique sinus, more or less upright, or horizontal, as the case may be. A junction at its base, of minute lines proceeding from either of its sides, forms a triangle. This distribution of the furrows, in which an oblique sinus is found, is by far the most common, and it may be considered as a special characteristic of man ; the furrows that are packed in longitudinal rows are, on the other hand, peculiar to monkeys. The vertex of the oblique sinus is generally inclined towards the radial side of the hand, but it must be observed that the contrary is more frequently the case in the fore-finger, the vertex there tending towards the ulnar
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