It is but seldom that medical evidence is required with regard to the identification of the living, though it may sometimes be so, as in the celebrated Tichborne case. The medical man may in such cases be consulted as to family resemblance, marks on the body, nÆvi materni, scars and tattoo marks, or with regard to the organs of generation in cases of doubtful sex. Tattoo marks may disappear during life; the brighter colours, as vermilion, as a rule, more readily than those made with carbon, as Indian ink; after death the colouring-matter may be found in the proximal glands. If the tattooing is superficial (merely underneath the cuticle) the marks may possibly be removed by acetic acid or cantharides, or even by picking out the colouring-matter with a fine needle. With regard to scars and their permanence, it will be remembered that scars occasioned by actual loss of substance, or by wounds healed by granulation, never disappear. The scars of leech-bites, lancet-wounds, or cupping instruments, may disappear after a lapse of time. It is difficult, if not impossible, to give any certain or positive opinion as to the age of a scar; recent scars are pink in colour; old scars are white and glistening. The cicatrix resulting from a wound depends upon its situation. Of incised wounds an elliptical cicatrix is typical, linear being chiefly found between the fingers and toes. By way of disguise the hair may be dyed black with lead acetate or nitrate of silver; detected by allowing the hair to grow, or by steeping some of it in dilute nitric acid, and testing with iodide of potassium for lead, and hydrochloric acid for silver. The hair may be bleached with chlorine or peroxide of hydrogen, detected by letting the hair grow and by its unnatural feeling and the irregularity of the bleaching.

Finger-print impressions are the most trustworthy of all means of identification. Such a print is obtained by rubbing the pulp of the finger in lampblack, and then impressing it on a glazed card. The impression reveals the fine lines which exist at the tips of the fingers. The arrangement of these lines is special to each person, and cannot be changed. Hence this method is employed by the police in the identification of prisoners.

In the determination of cases of doubtful sex in the living, the following points should be noticed: the size of the penis or clitoris, and whether perforate or not, the form of the prepuce, the presence or absence of nymphÆ and of testicles or ovaries. Openings must be carefully sounded as to their communication with bladder or uterus. After puberty, inquiry should be made as to menstrual or vicarious discharges, the general development of the body, the growth of hair, the tone of voice, and the behaviour of the individual towards either sex.

With regard to the identification of the dead in cases of death by accident or violence, the medical man's assistance may be called. The sex of the skeleton, if that only be found, may be judged from the bones of the female generally being smaller and more slender than those of the male, by the female thorax being deeper, the costal cartilages longer, the ilia more expanded, the sacrum flatter and broader, the coccyx movable and turned back, the tuberosities of the ischia wider apart, the pubes shallow, and the whole pelvis shallower and with larger outlets. But of all these signs the only one of any real value is the roundness of the pubic arch in the female, as compared with the pointed arch in the male. Before puberty the sex cannot be determined from an examination of the bones.

Age may be calculated from the presence, nature and number of the erupted teeth; from the cartilages of the ribs, which gradually ossify as age advances; from the angle formed by the ramus of the lower jaw with its body (obtuse in infancy, a right angle in the adult, and again obtuse in the aged from loss of the teeth); and in the young from the condition of the epiphyses with regard to their attachment to their respective shafts.

To determine stature, the whole skeleton should be laid out and measured, 1-1/2 to 2 inches being allowed for the soft parts.