Infancy is the period from birth till the first or milk set of teeth begin to be shed—usually about the seventh year. During this period the body increases in size and stature more, relatively, than at any other period of existence; and the mental faculties undergo great development. The milk teeth, twenty in number, are evolved in a definite order, beginning with the central incisors at about six months, and ending with the second molars about the termination of the second year. From the size and stature of the body, the development of the teeth, and the more or less advanced state of ossification or solidification of the bony skeleton, conclusions may be drawn as to the probable age of the infant.

Childhood extends from the commencement of the shedding of the milk teeth to the age of puberty—usually from the seventh to the fourteenth or fifteenth year. During this period the body expands, as well as the bony structures, without any clearly marked difference in structure being observable between the sexes except as regards the genitals, so that it is impossible to distinguish absolutely between the male and the female skeleton during this period. The milk-teeth are shed, and are replaced by the second or permanent set, thirty-two in number, though these do not usually all make their appearance during childhood. Marked differences between the proclivities of the sexes are noticeable even at an early period of childhood, and long before the characteristic functions begin to be developed.

Youth is marked at its commencement by the changes which occur at puberty—the development of the genitals in both sexes, the appearance of hair on the genitals, the appearance of a beard in the male, the development of the breasts in the female, the appearance of the monthly flow in the female, and the ability to secrete semen in the male. Marked mental changes now occur, and the generative functions are perfected. Youth terminates at tire age of legal majority, twenty-one years; or perhaps the period ought to be extended to twenty-five years of age, as it is with some nations.

Manhood (or Womanhood} is the period of perfection of all the bodily and mental powers. It ceases in woman with the cessation of the monthly flow at about forty-five years of age; but in man it often extends to a much later period of life.

Old Age begins with the decay of the bodily and mental faculties, and is characterized by wrinkling of the skin, loss of the teeth, whitening of the hair, and feebleness of the limbs. In its later stages decay of the mental faculties, deafness, obscurity or loss of vision, and bowing of the spine are added.

2. Duration of Human Life.— The chances of human life form an important subject of inquiry, which has been elucidated by the labours of Price, Milne, Farr, and others; and on deductions from comparisons of birth and death rates is founded the system of annuities, insurance against loss in sickness, and the insurance of lives. Since the establishment of compulsory registration of deaths, our knowledge of the ordinary and extraordinary chances of human life has been much extended, and surer data are now available for calculations of probabilities of life, of survivorships, and of the payments which ought to be made in benefit clubs. See Insurance and Longevity.

3. Personal Identity. —It might be imagined that there is little danger, with the exercise of ordinary care, of mistaking one person for another; but the remarkable case of the Tichborne claimant, and some other less-known but perhaps equally singular instances, have demonstrated that mistakes as to the identity of individuals are easily made, and are more frequent than is commonly supposed. Where the identity has to be established or disproved after long absence, exposure to foreign climates and great hardships, wounds, &c., the problem is often one of extreme difficulty. The data for identifying a person are individual and family likeness, stature, the colour of the eyes, peculiarities of garb and manner, recollection of antecedent events, but more especially marks on the person either congenital or acquired. Such are naevi or mother’s marks, scars, and disunited or badly united fractures, known to have existed upon the missing person. An accurate solution of the question is, nevertheless, often a matter of the greatest difficulty.

4. Marriage.— Under this head the medical jurist has to deal principally with the nubile age, viewed in the light of nature and according to legislative enactments, and with such physical circumstances as affect the legality of marriages, or justify divorce.

In Great Britain the age at which the sexes are first capable of propagating the species is later than in more southern climes. Ordinarily it does not occur before fifteen years of age for the male and fourteen for the female; exceptionally, however, it occurs at the ages of thirteen and of twelve (or even less) respectively in the male and female. By legislative enactment, nevertheless, parents and guardians may, in England at all events, forbid the marriage of young people till the age of legal majority. The only physical circumstances which in Great Britain form a bar to marriage are physical inability to consummate, and the insanity of one of the parties at the time of marriage. Both those circumstances have been pleaded and sustained in the law courts. In other countries minor physical circumstances, as disease, are held to invalidate marriage.

5. Impotence and Sterility.— These may arise from organic or from functional causes,— the former being alone irremediable, and as such taken cognizance of by the law courts. On this subject it is unnecessary to enlarge here.

6. Pregnancy.— This subject presents one of the widest fields for medico-legal evidence. The limits of age between which it is possible, the limits of utero-gestation, and the signs of pregnancy may all in turn be the subjects of investigation.

The limits of age between which pregnancy is possible are usually fixed by the appearance and cessation of the monthly flow; and these ordinarily begin about fourteen and cease at forty-five years of age. Exceptionally they appear as early as the tenth year, and may not cease till the end of the fifth decade of life. Cases, however, have occurred where a woman has conceived before menstruating; and a few doubtful cases of conception are recorded in women upwards of fifty, or even sixty, years of age. The general fact of pregnancy being limited by the age of puberty on the one hand and the cessation of the monthly flow—or fifty years as the extreme limit of age— must be accepted as the safest guide in practice.

The limits of utero-gestation are not in England fixed by legislation. The French code fixes the extreme limit of three hundred days. The ordinary period is forty weeks and a half, or two hundred and eighty-three days from the cessation of the last monthly flux. The limit of three hundred days, as fixed by the French code, is perhaps never exceeded, if ever reached. The uncertainty of females in fixing the exact date of conception has given rise to the discrepant opinions of physiologists on the subject. It is well known, however, that among the higher animals the period is not a precise one; and impregnation and conception are doubtless not necessarily coincident.

The signs of pregnancy are of the utmost importance to the medical jurist. He may be called upon to pronounce upon the virtue of a female, to sustain or rebut a plea for divorce, to determine whether a capital sentence shall be carried out, or to determine whether it is probable that an heir will be born to an estate. Should he err in his judgment—and mistakes are very possible iu the earlier months of utero-gestation—he may commit a grievous wrong. Medical jurists are in the habit of classifying the signs of pregnancy as uncertain or certain; it is the former which are most regarded by the public, but the latter are alone of probative value to the jurist. The usual and uncertain signs are the cessation of the monthly flow, nausea, sickness, a darkening of the areola and the formation of a secondary areola around the nipple, enlargement of the breasts, increased size of the abdomen, the formation of a tumour in the womb, quickening, and the motions of the foetus. There are also other minor signs of less importance. The certain signs are the uterine souffle, which is a peculiar soft sound heard over the abdomen, and synchronous with the maternal pulse; ballottement, or the examination for a floating tumour in the abdomen between the fifth and eighth months of pregnancy; and the pulsations of the foetal heart, heard by means of the stethoscope. These pulsations are much quicker than, and not synchronous with, the maternal pulse. This is the only indubitable sign of pregnancy. It is inapplicable before the fourth month of gestation.

7. Parturition.— The imminence of the process of parturition is of comparatively little interest to the medical jurist; but the signs of recent delivery are all-important. These signs are the bruised, swollen, and lacerated state of the external genitals, relaxation and dilatation of the vagina and womb, the existence of a peculiar vaginal discharge known as the lochia, a relaxed and fissured condition of the abdominal walls, a peculiar aspect of the countenance, and the distended state of the breasts due to the secretion of milk. Thelochial discharge is the most characteristic sign. All the signs may disappear within ten days of delivery, though this is not usual.

Connected with parturition, the question of viability of the child is not unimportant. After the intra-uterine age of seven months is reached a child is certainly viable. The period at which the foetus becomes viable cannot be stated with certainty; but five calendar months, or one hundred and fifty days, is perhaps the nearest approximation which can be made. The viability of a child is judged by its size and weight, its general state of development, the state of the skin, hair, and nails, its strength or feebleness, the ability to cry, and its power of taking maternal nourishment. The question of viability has important bearings upon the crime of infanticide, and the succession to property.

The subject of super∙foetation, or the possibility of two conceptions having occurred resulting in the birth of twins with a considerable intervening interval, is a very obscure one, and has given rise to much controversy,—its existence being affirmed by some medical jurists, and denied by others. There is much, however (e.g., the existence of a double or bifid womb), to countenance the view that a double conception is possible.

In the curious case of a man marrying a woman having possession of an estate of inheritance, and by her having issue born alive and capable of inheriting her estate, the man on the death of his wife holds her lands for life as a tenant by the “curtesy” of England. Here the meaning of “born alive” is different from the meaning of the same expression as used respecting infanticide. In questions of tenancy by the curtesy it has been decided that any kind of motion of the child, as a twitching and tremulous motion of the lips, is sufficient evidence of live-birth. As regards infanticide, proof of a conclusive separate existence of the child is demanded before live-birth is admitted.

8. Monsters and Hermaphrodites.— To destroy any living human birth, however unlike a human creature it may be, is to commit a crime. Blackstone states that a monster which hath not the shape of mankind hath no inheritable blood; but the law has not defined a monster, nor what constitutes a human form. The same author states that if, in spite of deformity, the product of birth has human shape, it may be an heir. Hermaphrodites are beings with malformations of the sexual organs, simulating a double sex. Physiologists do not admit, however, the existence of true hermaphrodites with double perfect organs, capable of performing the functions of both sexes.

9. Paternity and Affiliation.— These are often matters of great doubt. A considerable time may elapse between the absence or death of a father and the birth of his reputed child. As has already been said, three hundred days is the utmost limit to which physiologists would extend the period of utero-gestation. This subject in volves questions respecting children born during a second marriage of the mother, posthumous children, bastardy, and alleged cases of posthumous children.

10. Presumption of Survivorship.— Μ hen two or more persons perish by a common accident, when a mother and her new-born child are found dead, and in a few analogous cases, important civil rights may depend upon the question which lived the longest; and great ingenuity has been displayed in elucidating the disputes which have arisen in the law courts in such cases.

11. Maladies Exempting from Discharge of Public Duties frequently demand the attention of the medical man. He may be called upon to decide whether a man is able to undertake military or naval service, to act as a juryman without serious risk to life or health, or to attend as a witness at a trial. An endeavour to give a fearless and honest certificate should animate the medical man in the discharge of this delicate duty.

12. Feigned and Simulated Diseases often require much skill and acuteness in order to detect the imposture. Where there is reason to suppose that a disease is simulated, much caution as to procedure is also required.

13. Insanity or Mental Alienation.— This subject presents an enormous field to the medical jurist. A medical man may be required to give evidence in any of the law courts, civil, criminal, or ecclesiastical, before commissions de lunatico inquirendo, or before a magistrate, as to the sanity or insanity of an individual; and he may have to sign certificates of unsoundness of mind with the view of providing for the safe custody and proper treatment of a lunatic. Hence he must be familiar with the chief forms of insanity (see Insanity), and be able to distinguish and treat each of these. He will also be required to detect feigned insanity, and to examine persons charged with crime with the view of preventing real lunatics from being treated as criminals.

The terms “unsoundness of mind,’’ applied to the condition of the mind itself, and “non compos mentis ” to the person whose mind is affected, are legal terms applied to insanity. Lawyershave disputed as to whether imbecility should or should not be included under the head of insanity; but medical men include under this category all disorders or defects of the mind which disqualify a person for managing his affairs, and entering into a binding contract, or which render the individual morally irresponsible for his or her otherwise criminal actions. There is good legal authority for recognizing four forms of unsoundness of mind— idiocy, dementia, mania, and monomania.

The chief questions respecting unsoundness of mind which present themselves to the medical jurist are—is the person of sound or unsound mind; if unsound, are there real lucid intervals; is he fit to manage his affairs, to contract a marriage, or to execute a will; is lie dangerous to others Ί

As grounds for restraint, the law recognizes only these conditions—danger to himself, inability to manage his own affairs and property, and danger to the person of others. Before an individual can be placed under restraint in an asylum the certificates of two medical men must be obtained, and the formal order of a relation or friend. The certificates to be valid must be signed by legally qualified medical practitioners having no interest, direct or indirect, in the patient, or in the asylum to which be is to be sent. The medical examiners must pay separate visits, each medical man examining the patient separately. The certificates, which remain valid for seven days only, must bear the exact address of the lunatic, his occupation, and the date of the examination; they must also set forth distinctly the grounds of the opinion they express, under the separate heads of facts observed by the examiner, and facts (to be specified) communicated by others. In the case of pauper lunatics one medical certificate only is required, which is supplemented by an order from a justice of the peace. In urgent cases also one medical certificate suffices for incarceration in an asylum, provided that within three days of the patient’s reception two other such certificates are signed by two other medical practitioners, not being connected with the asylum, upon a like examination. The superintendent or proprietor of the asylum must in all cases forward to the commissioners of lunacy a notice of admission within one clear day from the patient’s admission. Any infringement of the statutory regulations subjects the person who commits it to a heavy penalty.

II. Injuries to tπe Person.

1. Defloration.— The signs of defloration are obscure and uncertain; and it is rather by the coexistence of several of the usual marks than the existence of any one sign, that any just conclusion can be arrived at.

2. Rape. —This crime consists in the carnal knowledge of a woman forcibly and against her will. The resistance must be to the utmost, else the crime of rape has not been committed in the legal sense of the word. The proofs of rape, accordingly, apart from the consistency of the woman’s story, mainly depend on the presence of the signs of defloration, and on marks of injury on the man.

3. Mutilation.— This may consist in the cutting or maiming of any member; castration is the most important, and perhaps but rarely effected as a crime. Self-mutilation, giving rise to false accusations, is occasionally resorted to.

4. Criminal Abortion.— The crime of abortion consists in unlawfully administering to a woman, or causing to be taken by her (whether she be with child or not), with intent to procure her miscarriage, any poison or noxious thing, or using for the same purpose any instrument or other means whatsoever; also in the use of the same means, with the same intent, by any woman being with child.

5. Homicide.— The legal sense of the term homicide excludes such injuries as are the result of either accident or of suicide. It embraces murder or wilful homicide, manslaughter or culpable homicide, casual homicide, and justifiable homicide.

As a preliminary in all cases of homicide, it is the duty of the medical jurist in the first place to ascertain the fact of death, and to distinguish between real and apparent death; and then to determine, if possible, the period at which death took place.

Infanticide or child murder is by the British law treated with the same severity as the murder of an adult. Indeed infanticide as a crime distinct from murder has no legal recognition. Practically this severity defeats itself, and offences which are really cases of child murder are often treated simply as cases of concealment of birth. The iniquity of the old law which threw the onus of proof of still-birth on the mother now no longer exists, and the law demands strict proof of live-birth at the hands of the prosecution. Hence the subject involves very nice points of forensic medicine. The chil∣l must be proved to have arrived at the period...