We shall now proceed to consider the Seven Ages of man in detail.
Infancy—Infantia—(from Infari, not able to speak) commences at birth, and terminates at the seventh year. The signs by which the age of an infant may be computed, are derived from its moral as well as physical characters; and as circumstances connected with medico-judicial inquiries may render the problem of importance, we shall proceed to offer some data that may assist its solution. The feebleness and size of the infant; its epidermis yet reddish, and wrinkled; its face covered with down; its head soft, and the fontanelles greatly extended; the eye but little sensible to light, and lastly the appearance of the navel, are circumstances which will at once lead the medical practitioner to the conclusion of its not being many days old; while its smiles and tears, its upright posture in the nurses arms, the thickness and whiteness of the skin, the plumpness of its thighs and buttocks, the eagerness with which its eyes seek and follow brilliant objects, its agitation on the occurrence of noisy sounds, and its eager desire for the breast, are occurrences which will, according to the force and degree of each, announce the child’s progress towards the third, fourth, or fifth month. The pleasure which it testifies at the sight of its nurse, its jealousies, and other passions, the habit of carrying its fingers and different objects to its mouth, the facility and pleasure with which it chews bread, and the copious discharge of saliva, announce the approach of dentition, and assure us that the infant must be in its seventh month. The progress of dentition will at this period afford some farther data; towards the end of the seventh month the middle Incisor teeth of the inferior jaw perforate the texture of the gums; and soon afterwards the corresponding Incisors of the upper maxilla make their appearance; then the lateral Incisors of the inferior, and subsequently those of the superior jaw; about the twelfth or fourteenth month, sometimes sooner, the first of the Molares of the under, then the corresponding teeth of the upper jaw appear; the four Cuspidati are usually protruded through the gum the last; thus the Cuspidati and the second Molares will sometimes appear at the same time, and this is usually between the twentieth and twenty-fifth month; so that at, or soon after two years of age, the twenty temporary or milk teeth[[269]] are to be found in situ. It must however be remembered that the formation and appearance of the milk teeth are subject to considerable variety, and there are some examples on record, though very uncommon, of children born with two Incisors in the upper maxilla, but such teeth have been found to be imperfect in their structure, and without fangs, and they have consequently soon been detached; in other cases, children, although enjoying perfect health, have not cut a single tooth until the end of their second year. Nor are the other signs to which we have alluded, as affording indications of the age, to be considered as immutable; the infant may have been more or less retarded, or accelerated in its march of developement by its state of health and vigour, and it deserves remark, that scrophulous and rickety children very commonly present an aspect of intellectual precocity, by no means commensurate with their age; and hence the popular notion has arisen, that very intelligent children rarely continue to live. The fact of this premature expansion of the mind is too apparent to be doubted; but philosophers have endeavoured to explain it upon very different principles; the physiologist has sought the cause from some peculiarity in the organization of the body, while the moralist has attempted to account for it by supposing that in consequence of the inability of these subjects to partake of the sports and exercises suitable to their years, they necessarily enjoy more of the instructive society of their parents and preceptors.
Pueritia—Second Infancy—Boy-hood. At about the age of Seven years, Detentition, or the shedding of the temporary or milk teeth commonly commences, in order to make room for the adult set; and this event is considered as marking the arrival of the second epoch, and which, in its turn, is terminated at fourteen or fifteen in boys, and at twelve or thirteen in girls, by that peculiar change which the constitution undergoes, and which we have hereafter to consider under the head of Puberty. Persons of this second age are called Pueri, or Impuberes, not being considered as yet in possession of the complete powers of reason, although they may be allowed to possess some faint ideas with regard to the customs and habits of society; their memory is also most clear and comprehensive, but it soon becomes governed by the imagination.
Adolescence or Puberty.—This important and tumultuous epoch of our existence commences at about fourteen in males, and at twelve in females, and ends at twenty-one, or later according to constitution, habit, and climate. The body having nearly completed its stature, its powers of growth are directed into other channels; and in the male, the beard begins to sprout; the voice becomes fuller, deeper, and more sonorous;[[270]] the parts of generation acquire the magnitude which they afterwards preserve, and become shaded with hair; the whole volume of the body augments, and at the same time assumes a character so decidedly masculine, as at once to proclaim the sex of the individual in whom it appears; in addition to these general changes, the secretion of the seminal liquor by the testicles commences, and the individual thus irritated by new desires, soon distinguishes the means of gratifying them, and the life of the species may be said to commence its existence. Nor are the moral changes which take place less remarkable, or less characteristic of the period of puberty than those which appertain to his physical condition; his mind acquires increased tone, and his manners and habits assume a more manly character; these changes however do not immediately succeed, and we are much inclined to admit with Zacchias[[271]] the existence of three gradations in Adolescence, Incipient Puberty (at about fourteen), Puberty (from seventeen to twenty), and Perfect Puberty (from twenty to twenty-five). These distinctions are undoubtedly founded in nature, and are admissible both in relation to sexual and intellectual maturity. Important changes likewise occur at this critical age, with respect to the extinction or kindling of disease; in cases of hereditary predisposition, the particular malady will frequently remain dormant until the age of puberty; this is particularly evinced in maniacal affections,[[272]] in consumption, and other scrophulous diseases. The phenomena which attend the accession of puberty in females are not less remarkable than those which we have described as occurring in males; and although there is neither the change of voice, nor the production of hair on the face, so remarkable in the other sex, yet the body enlarges in volume, the breasts swell with exuberance, and the excess of vitality no longer required for general growth, invests her limbs with those rounded and graceful forms, which have so universally constituted the theme of the poet, and the admiration and study of the artist: but the most remarkable change which the female system undergoes at this period is indicated by the commencement of a periodical sanguineous discharge[[273]] from the vessels of the uterus, and which from the monthly interval that it observes has received the name of Menses. The period of life at which this change takes place is under the control of various moral and physical circumstances, as climate, temperament of the individual, habits of living,[[274]] &c. In tropical climates puberty takes place at an earlier period than in northern latitudes; in Greece, the Corea, Indostan, and Java, girls begin to menstruate at eight, nine, or ten; in Spain, Sicily, and the Southern part of Europe, at twelve; but advancing to the northern climes, there is a gradual protraction of the time until we come to Lapland, where women do not menstruate till they arrive at a maturer age, and then in small quantities, at long intervals, and sometimes only in summer.[[275]] This difference in the time of life at which puberty takes place, has been ingeniously assigned by David Hume as the reason why women in hot climates are almost universally treated as slaves; and why, on the contrary, their influence is so powerful and extensive in colder regions; for in the former, woman may be said to be in the zenith of her beauty while she is yet a child in understanding, and long before her intellect is matured she ceases to be an object of love; but in temperate countries her personal charms and intellectual endowments are simultaneous in their progress to perfection; the united force of her beauty and mental qualities is irresistible, and man voluntarily pays to her the homage which her powers are so well calculated to command[[276]].
There are, moreover, many cases on record[[277]], in which both males and females have prematurely arrived at the stage of puberty; a most remarkable instance of this precocity is recorded[[278]] by Mr. Anthony White, in the history of Philip Howorth, and the author of the present work can bear testimony to the correctness of the statement, for he had frequent opportunities of seeing him, and of tracing from time to time the constitutional changes which so rapidly succeeded each other in the first two years of his existence. Dr. Wall has presented us with a similar instance of precocity in a female infant, in whom the menstrual flux appeared at the age of nine months[[279]].
Various methods have, at different times, been adopted for determining the age of puberty. One sect of ancient Roman lawyers, called Cassiani, fixed it by the state of the body, which Justinian and others after him suppose to have been done by a personal examination, at least in the male sex; for as to the female it is pretended that the twelfth year was the only guide; though others allege that the eruption of the menses served instead of it. The Proculiari, on the contrary determined the puberty of males by the expiration of the fourteenth year. Javolenus pursued a middle course, and made use of both methods.[[280]].
The phenomena of puberty depend, in both sexes, upon the developement of the generative organs; for whenever this is prevented, or only imperfectly produced, a corresponding character is impressed upon the individual, as we see so well exemplified in the appearance of eunuchs[[281]]. In females, however, the uterus does not appear to be the essential organ which impresses the sex with its distinctive peculiarities: Van Helmont has said “Propter solum uterum mulier est, id quod est”——but Dr. Caillot has shewn in the second volume of the Medical Society of Paris that a woman may grow up with all the external appearances and attributes of her sex, and yet have no uterus; numerous cases of a similar kind are upon record, to some of which we shall have occasion hereafter to allude: the same facts do not hold good in relation to the Ovaria; their developement, like that of the testicles in the male, seems to be absolutely essential to the perfection of the sex. A very interesting case,[[282]] in illustration of this truth, is afforded by Mr. C. Pears; in which account all the characters belonging to the female after puberty were absent; her breasts never enlarged, she never menstruated, no hair appeared on the pubes, and she died at the age of twenty-nine; when upon dissection the Ovaries were found wanting; the os tincæ and uterus had their usual form, but never increased beyond their size in the infant state.
Juventus—Youth.—This succeeds to adolescence, and in its turn is replaced by manhood. If the law does not acknowledge this stage of life, it at least tacitly allows it, as being the one best adapted for the vigorous discharge of public duties; it is the age at which the greatest enterprizes have been achieved, and the most brilliant efforts of human genius fulfilled; the developement of the body having been accomplished, its powers are expanded in the production and support of intellectual energies. The action of the arterial system may be said to predominate over every other, and hence the diseases to which man is exposed in this stage of his existence are of an acute and inflammatory character. To the common observer his march of life would seem to be arrested, little material change, either of a moral or physical nature, is discernible from the age of twenty-five to thirty-five; and this period may therefore be said to occupy a part of the second great division of Aristotle to which we have alluded (the period of Perennity.)
Ætas Virilis—Manhood. Youth passes into manhood by such insensible shades of gradation, that it has been considered as only a continuation of the same stage of perennity; and yet we shall find that the change from one to the other is sufficiently striking to entitle them to distinct places in the scale. Hippocrates and Galen have compared youth to the summer, and manhood to the autumn, thus insinuating that if one be less fervent, it is yet more mature than the other; and this is certainly morally and physiologically true; for although the imagination loses much of its glowing fervour, its dominion is succeeded by that of a maturer judgment; the arterial system no longer predominates over every other, its energies have been reduced, and a juster equipoise established; the diseases, therefore, to which he is liable assume a different aspect,[[283]] and maladies of a chronic character prevail, and thus while in the apparent plenitude of his existence is he fast journeying to his destined goal;[[284]] man never stands still, he is either progressing to the zenith of his strength and vigour, or he is declining from it; in vain shall we attempt to cast our anchor in the stream of life, it will alike carry away those who struggle against it, and those who yield quietly to the force of the current; the panaceas and boasted elixirs, and the many other means which have been proposed to renovate the body, are as chimerical, says Buffon, as the fountain of youth is fabulous.
Senectus—Old Age. The system has now undergone a considerable change; its bony framework has acquired increased solidity and density; the vascular system is greatly abridged in the extent and subtlety of its ramifications; the muscles become less irritable, their fatty matter is absorbed, the cellular structure collapses, and the whole volume of the body diminishing.