Congenital Deformities.—These offer no difficulty and are in many cases permanent, such as intra-uterine amputations, constrictions, abnormality of limbs, &c. Such conditions as hare-lip, cleft-palate, herniæ;, &c., may be altered by surgical procedure, but leave permanent records of this. Peculiarities in twins are interesting as to their being of the “mirror image” or “identical” type.
Anthropometry.—This is principally used for the identity of habitual criminals. The Bertillon method is based upon certain measurements of the body, the principal of which are (1) the length of the head, (2) width of head, (3) length of body, (4) length of trunk while sitting, (5) distance between tips of mid-fingers with arms outstretched, (6) length of left forearm, left middle finger, and left foot, (7) length and width of right ear, (8) colour of irides. These measurements place the person in one or other class, according to the special system of classification.
Fig. 1.—First line (from left to right), plain impressions of whorl (thumb), arch (second finger), radial loop (forefinger).
Second line, rolled impressions of whorl (thumb), ulnar loop (fourth finger).
Finger Prints.—These are largely used as a means of identification in criminal cases, either by prints left upon articles, or by prints definitely made by the police authorities as a record for identification purposes.
On articles, the finger prints may be rendered more visible by dusting with some finely powdered material of dark colour which will adhere to the impression, which may then be photographed and enlarged.
For purposes of record, the impressions are taken directly upon a suitable surface of the bulbs of the fingers and thumbs after having coated them with printer‘s ink. The impressions thus made show individual peculiarities in the distribution and arrangement of the ridges of the skin; and the chances of the markings of two individuals being alike is about one in sixty-four millions. By means of the pattern of these ridges, prints may be classified under the headings of arches, whorls, and loops, with certain recognised modifications of these. (See [Figs. 1] and [2].)
Fig. 2.—First line (from left to right), plain impressions of whorl (forefinger), ulnar loop (thumb), arch (second finger).