We have here, then, a well-defined term, which gives us precisely the period of growth; and the duration of growth gives us the duration of life. All the phenomena of life are connected one with another by an uninterrupted chain of relations: the duration of life is given by the duration of gestation, the duration of gestation again by the size of the animal. The greater the animal is, the more is the period of gestation prolonged the gestation of the rabbit is 30 days; that of man, 9 months; that of the elephant is nearly 2 years. The duration of life in the elephant has never been satisfactorily determined. Aristotle says it lives 200 years; Buffon at least 200; Cuvier says nearly 200; others say 120, 130, 140, 150, up to 400 or 500 years. Certain it is, that it is the longest-lived animal that is known, or, as Blainville justly calls it, "the most extraordinary animal in the whole creation." A single observation as to the epoch at which the union of the long bones with their epiphyses takes place would, according to Flourens' views, determine the duration of the life of the elephant, of the rhinoceros, of the hippopotamus, and of all such gigantic animals, the duration of whose lives is at present

unknown.

It is very consoling to learn that scientific investigation grants to man an ordinary duration of life equal to 100 years; but this is not all. There is also an extraordinary longevity, or an extreme duration of life, which the celebrated physiologist Haller estimated from two instances, one of 152 years, the other of 169, at two centuries. Flourens, on his side, asserts that experience demonstrates that in the mammiferæ the extraordinary life may be prolonged to double the duration of ordinary life. In the same manner as the duration of growth multiplied five times gives the ordinary duration of life, so that ordinary duration multiplied twice gives the extreme duration of life.

A first century of ordinary life, and almost a second century-at the least a half century-of extraordinary life, is, then, the perspective offered by science to man. It is true that, to use the language of adepts, science offers us this vast fund of life rather as a power or principle than as an act; plus in posse quam in actu; but had it pleased Providence to ensure it to us, the lamentations of men at the brevity of life would not have been the less. "Tell me first," says Micromégas, "how many senses have the people in your globe?" "We have seventy-two," answered the inhabitant of Saturn, "and we complain every day of the paucity." "I can easily imagine that," said Micromégas, "for in our globe we have a thousand, and yet we are very far from being satisfied." Man, then, who does not perish from accidental causes, lives for 100 to 150 years. Few men die of old age. Thomas Parr, having attained a celebrity by his old age, King Charles I. expressed the wish to see him at court. He was too well treated there, and he died of indigestion. Harvey performed the autopsy of the old man's body. All the viscera were perfectly healthy, the cartilages of his ribs were not even ossified; he might have lived many years more, but he perished at 152 years of age by an accident. Man has made for himself a kind of artificial life, in which the moral is more frequently diseased than the physique, and in which the physique is also much more frequently ill than it would be if the habits of life were more serene, more calm, more constantly and more judiciously laborious. "Man," writes Buffon, "perishes at all

ages, whilst animals seem to pass through life with a firm and equable pace. The passions, and the misfortunes these bring in their train, affect health, and disorder the principles which animate us. If the lives of men were more carefully observed, it would be found that almost all live a life of mixed strife and apprehension, and that the greater part die of

care or sorrow."

Before, however, we discuss the philosophy of longevity, we must consider life in its twofold aspects, as one of growth and one of decline-two aspects which divide it into two nearly equal portions. According to Flourens' system, these two halves are again subdivided into two others, and from thence the four ages of life: childhood, youth, manhood, and old age. Again, each of these ages divides itself into two. There is a first and a second childhood, a first and a second youth, a first and a second manhood, and a first and a last old age.

Flourens proposes the following as the duration of these different ages or epochs: for the first childhood, from birth to 10 years of age, that is childhood properly speaking; and for the second, from 10 to 20, that is adolescence; for the first youth, from 20 to 30; and for the second, from 30 to 40; for the first manhood, from 40 to 55; and for the second, from 55 to 70. Manhood, taken in its ensemble, is the epoch of strength and perfection, as is well expressed in the term of the period of virility. The first old age begins at 70, and lasts till 85 years; and at 85 begins the second and last old age.

This exceeding prolongation of the different ages, which will appear to correspond more to what theoretically should be the case than to what virtually is so, is founded on the fact that at 10 years of age the second teething terminates; at 20 years of age the development of the bones ceases; and at 40 years of age increase of growth has an end, and whatever augmentation there is in volume is mere fatty accumulation. A last condition, which Flourens designates as one of invigoration-an internal, deep-seated action, which, extending to the most remote tissues of the body, gives to them all firmness and finish, and renders all the functions more perfect and all the organs more complete-takes place from 40 to 55 years of age, and prolongs itself afterwards, more or less, to 65 or 70 years.,

At 70 old age commences. The physiologists of olden times used to distinguish two kinds, or rather two provisions of forces-the forces in reserve and the forces in use; or, as they expressed it, vires in posse, et vires in actu; or, as Barthez called them, the radical forces and the acting forces. In youth there is a large amount of force in reserve: it is the progressive diminution of these disposable forces which give to old age its physiological character. So long as an old man only employs his active powers, he does not perceive that he has lost anything; but the moment that he exceeds the limits of his usual active powers, he feels fatigued and exhausted; he perceives that he has no secret resources, and that the abundant forces in reserve in youth-time are no longer at his command.

"When one knows," M. Reveillé Parise remarks in a very able work on old age, "that there is in each of our organs two particular forces, which, although in reality identical, are, the one daily and habitual and always in use, the other secret and in reserve, only manifesting themselves

upon extraordinary occasions, a wise man is induced never to commit an excess. It is, indeed, upon the occasion of these excesses that the employment of the forces of reserve is necessary; but as these forces can only be recovered with difficulty and after the lapse of a greater or less time, it will be felt that they should be had recourse to as seldom as possible, and that more particularly in old age, when the organism is weakened by the lapse of years."

M. Reveillé Parise argues that the period of general decline begins with the lungs; but M. Flourens, we think with great justice, combats this idea, and considers old age not as a local but as a general phenomenon. Nor is it, indeed, always the same organ in which the effects of age are first manifested, but rather in one or another, according to circumstances and to individual constitutions. In considering the manner in which old age operates, it is important to remember that the principle of life, whatever may be its nature, is eminently an exciting, an impulsive, and a motive power. "It is taking a very false notion of life," says Cuvier, "to consider it as a simple bond which keeps together the elements of the living body, whilst it is, on the contrary, a spring that moves them and transports them incessantly. There is an incessant mutation and renovation of parts going on; force alone is persistant, matter constantly changing; we cannot keep what we have, we can only keep repairing what is lost; with old age the forces, by which form is sustained amidst a continual waste, begin to decline, till they ultimately fail altogether, which would be a natural in opposition to an accidental death."

But while we cannot grow aged without a decline of our physical powers, the moral and intellectual man rather gains by increase of years. Who has not read the "Treatise on Old Age" of Cicero? a work of which Montaigne said, "It gives me a wish to grow old." Another work on old age, the effect of which is most consoling and instructive, and to which we shall soon refer more at length, is that of Louis Cornaro. The book of Cicero convinces, because it is written with a master's hand, and under the inspiration of an elevated philosophy. That of Cornaro carries with it the reader, because it is written by a wise and amiable old man, who has lived a hundred years, always cheerful, always gay, always happy to live. Here the fact convinces still more than the book.

"In green old age," M. Reveillé Parise says, or from 55 to 75 years and beyond that, intellectual life possesses a remarkable consistency and solidity; it is truly the age at which man attains the perfection of his faculties." What M. Parise calls "green old age," it is to be observed, corresponds to what M. Flourens calls "the first old age.'

The celebrated anatomist, Duverney, addressed public bodies with all the vivacity and energy of youth at the age of 80. La Fontaine penned some of his best verses at 73; Voltaire was most philosophical at 78. These may be called exceptions-they are not so, they are revelations; they show how, under proper conservative circumstances, certain faculties remain vigorous and intact. In youth, attention, lively and active, receives impressions quickly, but reflection is wanting; in manhood, reflection and attention are combined, and that is what constitutes the force of a ripe age; in old age, attention begins to fail, but reflection

we

increases; old age is the epoch when the human heart turns back upon itself and knows itself best. Buffon called old age a prejudice. "Without our arithmetic," says the active-minded naturalist, who wrote his best work, the "Epoques de la Nature," when he was upwards of 70, 66 should not know that we are getting old." The philosopher, Fontenelle, said at 95 years of age, that the happiest period of life is from 55 to 75; at that epoch our lot is established, reputation made, condition in life settled, pretensions discarded or fulfilled, passions calmed, and the place which a man is destined to fill in society determined. He has no longer any illusions, any vain desires or foolish wishes to torment him; he sits down soberly to enjoy the position in which it has pleased Providence to place him.

Needless to say that a century of normal life, and, still less, two centuries of extreme longevity, are not to be obtained without conditions of a most rigorous character: there must be good conduct and almost incessant occupation, work or study, and, above all, moderation and sobriety in everything. The greatest writers on the physiological conditions of longevity are, beyond compare, Hufeland, who entitles his work "The Art of Prolonging Life;" Cornaro, who calls his "On a Sober Life," but adds, "Means of Insuring a Long Life;" Reveillé Parise, who defines hygiene to be "the art of justly estimating one's powers, and of exciting and sustaining them so as to preserve life the most possible, the best possible, and the longest possible." To these we must add the two Combes, the physician and the philosopher, the one in his work on Physiology, the other in his work on the Constitution of Man, both advocating that enlightened obedience to the Natural laws, without which there is neither health nor happiness, and most assuredly not longevity. The principles advocated in the present work by M. Flourens reduce themselves to precisely the same category.

It is a most singular fact in the history of the human mind-a most remarkable psychological feature of human society as at present constituted that while the desire of self-preservation, and of protracting the short span of life, is so intimately interwoven with our constitution, that it is justly esteemed one of the first principles of our nature, and, in spite even of pain and misery, seldom quits us to the last moments of our existence, that few are found to obey the most simple dictates of prudence in the ordinary conduct of life. Evil example, and, we fear to say, ignorance, are first causes, habit another, and all combine to entertain that state of things upon which that law of mortality is founded which is the basis of Life Insurance. Uncertain as is the life of any one individual, it is very well known that if two different numbers of individuals, at or near the same age, be taken, the number that will be left at the end of a few years will be nearly the same, if they exist during that time under similar circumstances. All Life Insurance Companies have to assume this latter condition of the same state of habits of society. Was any state of things to arise by which there would be less necessity for a killing competition in labour and professions; was greater sobriety and moderation commonly practised-and by sobriety we do not mean mere abstinence from fermented liquors, but general steadiness of conduct and pursuits, and the avoidance of all excesses in labour and diet-were the passions better regulated, were there a less unequal distribution of wealth,

and not gluttony, idleness, and fastidiousness on the one side, opposed to squalid want and merciless debauchery on the other; were the sanitary laws not a matter of mere talk from Central Boards and Boards of Guar dians, but a legal and scientific reality; and were, above all things, the Natural laws observed religiously by every one, as the great principles of existence, as an imperious duty towards ourselves and others, and their infringement considered to be, as it is, an act of the grossest ingratitude towards our Creator, the "Carlisle Tables" would no longer do for the office calculations of the Life Insurance Companies. Few instances are more striking than the life of Louis Cornaro of the effects of moderation in prolonging life. Cornaro had naturally a very delicate constitution; in his youth he indulged in the dissipated life of his time, his health gave way, and at thirty-five his medical advisers gave him only two years to live. He determined from that moment to reform; he changed a dissipated life for a regular one, and intemperance for sobriety. His moderation was even carried to excess. Twelve ounces of solid food, and fourteen ounces of wine, were all that he took daily, for upwards of half a century. This amount of food, which includes bread, meat, and game-for he was an advocate for variety, so long as it was easily digested-was divided into four meals. When he got very old, he is said to have made two meals upon the yolk of one egg!

"I have always been healthy," says the old man in his work, "since I have been sober." But Cornaro did not look solely to moderation for a long life. "I so manage," he says, "as to avoid extremes of heat or cold; I never indulge in violent exercise, I avoid late hours, I shun all places where the air is impure, and I have always been careful not to expose myself to a strong wind, or the excessive heat of the sun."

Nor did he pay less attention to the moral and intellectual man. "I found," he says, "my condition to improve materially by not giving way to sorrow, and by banishing all such thoughts as were likely to beget care." He had eleven grandchildren, and he delighted to see them happy and playful in his presence. He likewise took an active interest in the welfare of his tenantry. Whilst he thus cultivated his moral being by the most healthy exercise of the heart, he sustained his intellectual powers by literary and scientific pursuits. At eighty-three years of age he penned a comedy for his own amusement; and he assisted materially in the embellishment and improvement of Venice, by his considerations on the lagoons by which that city is surrounded. (Trattato delle Acque, 1560.)

A remark of Cornaro's, which Flourens delights to improve upon, is as follows: "That which gives me a real pleasure is to see that age and experience can give a man more learning than the schools. Few know the real value of ten years of a healthy life, at an age when a man can enjoy all his reason, and profit by all his experience. To speak only of the sciences, it is certain that the best works we have were written in those last ten years which the dissipated affect to despise; it is certain that the mind perfects itself in proportion as the body grows older: science and art would have lost much if all the great men who have cultivated them had shortened their days by ten years."

"I entirely agree with Cornaro," writes M. Flourens, "that the mind perfects itself in proportion as the body grows older. Each age