SURFACE SIGNS OF IDENTITY.
Examination of the surface of the skin and of its appendages may in certain cases take decisive importance. Valuable medical proof is often furnished by scars, nævi, growths on the skin, pock-marks, traces of skin disease or of scrofula, and by the so-called professional stigmata which would suggest the trade, character of work, or occupation of the deceased. Thus cigarette-stains on the fingers of smokers, or silver-stains on the hands of photographers, the horny palm of the laborer, or the soft, delicate hand of one not accustomed to work, would be indicative. The alterations in the hand make it, so to speak, the seat of election; for in the majority of trades that may be mentioned it is the hand alone that bears the principal marks of daily work that indicate the calling. A case is recorded of a person who previously to his assassination was lame and walked with a crutch. Although the body was cut into fragments, an examination revealed in the palm of the hands characteristic callosities, showing prolonged use of support of this kind. In another instance of criminal mutilation a tattoo-mark found on the arm proved an overwhelming charge against the assassin and drew forth his confession. An accused was also convicted of murder after establishing the only missing link, the question of identity, which turned on the finding of cupping-marks and a tattoo on the body of the murdered man. Personal identity of the bodies of infants has, moreover, been proved by means of a small blister; by a patch of downy hair; by the similarity existing between two pieces of thread used to tie the umbilical cord; and by the severed end of that part of the funis attached to the infant fitting precisely to the corresponding portion attached to the after-birth. In addition to these a methodical examination may put in evidence other facts that may be derived from diverse influences that leave characteristic traces.
SIGNS FURNISHED BY MARKS, SCARS, STAINS, ETC., ON THE SKIN.
But of all the surface signs, whether congenital or acquired, that may throw light on the antecedents of the decedent, birth-marks, freckles, cicatrices, tattooes, and the professional signs furnish the best indications. Birth-marks (nævi materni), from their supposed indelibility, have given rise to discussion at many celebrated trials. As a rule, these marks are permanent and seldom lose their distinctness, though in exceptional cases they may undergo atrophy in the first years of life. Hence testimony as to the existence of birth-marks may often be uncertain when it has reference to a period a long way back. In a recorded case of supposed recognition of a person having a mark of this kind on her face, the alleged victim turned up and established her identity as well as the fact that she did not have the birth-mark attributed to her.
Before the introduction of the electrolytic method it was customary to resort to cauterization, excision, vaccination, and tattooing the pigmentary spot in order to modify or remove these congenital marks. Such proceedings usually left more or less of an indelible scar which occasion might utilize in the matter of medico-legal diagnosis. The traces of nævi may, however, be entirely removed by electrolysis. I have recently seen a nævus of large dimension on the face of a young woman so completely destroyed as to leave no trace of the operation.
The possibility of the disappearance of a scar in such circumstances depends here, as it does in other instances, on the depth of the wound. A cicatrix being the result of a solution of continuity in the derma, the question arises whether a wound that has divided the derma without loss of substance and healed by first intention leaves any perceptible scar. Some are of the opinion that a cicatricial line persists, but grows fainter with time. Histological examination in a question of this kind might prove conclusive by showing the structure of the fibrocellular tissue that constitutes the cicatrix. In the case of very superficial burns or wounds, the scar may completely disappear if the epidermis alone or the superficial part of the derma is attacked; on the other hand, if there has been long suppuration or loss of substance from ulcers, chancres, or buboes, especially on the neck, groins, legs, or genital parts, traces of their lesion will be found. It may, therefore, be asserted as a general rule that all scars resulting from wounds and from skin diseases which involve any loss of substance are indelible. A scar on the face is one of the points at issue in the celebrated Hillmon case already mentioned.
As the matter of cicatrices is treated in the section on Wounds, further mention here would be superfluous.