What are the circ.u.mstances most favourable to longevity? This question is not easily answered; for we find in instances of advanced age that some individuals have led a most regular and abstemious life, while others have indulged in various excesses. These observations, however, are by no means calculated to form a conclusive opinion, as the const.i.tutional vigour and peculiar idiosyncrasies of individuals differ widely. It is probable that a regular mode of living is the most likely to prolong our years, whatever may be that regularity in a comparative point of view. A sober man, who commits occasional excesses, is more likely to suffer than another man who gets drunk every night, provided that these excesses do not differ in regard to the quant.i.ty or quality of stimulus. In these melancholy instances the excitement is constant, and the indirect debility which it may produce has scarcely time to break down the system ere it is again wound up to its usual pitch, to use the vulgar expression, "by a hair of the same hound." The princ.i.p.al attribute of life that renovates for a while its moral and its physical exhaustion is _excitability_, and a constant _excitement_ is therefore indispensable, to serve as fuel to the consuming fire. This was to a certain degree the basis on which Brown founded his doctrine. He traced a scale of life like that of a thermometer,--health in the centre, death at each extremity: one scale ascending from health was graduated according to stimulating agency, the other to debilitating causes; and therefore the system was to be stimulated or lowered according to this gradation. It would be foreign to this work to point out the absurdity of this theory, although we must admit its ingenuity, and to a certain extent its correctness. The chief practical objection to it was the diversity of const.i.tutions and idiosyncrasies, and the different action of stimulating or depressing agents in health and in disease; the effects of alimentary and medicinal substances being totally different in these several conditions.

According to habit, a certain sum of stimulus is requisite to keep up the necessary excitement; and this sum cannot be immediately and suddenly withdrawn in weak subjects without some risk; in health, perhaps, the experiment may be safely made at all times, and under any circ.u.mstances, although it might be wiser to operate the change by degrees; and it must moreover be recollected, that an habitual drunkard is in a morbid condition, and must be treated accordingly.

Six causes chiefly exert their influence upon life:

1. Climate and soil.

2. Difference of races.

3. Complexion and stature.

4. Period of development during gestation, and of subsequent growth.

5. Mode of living.

6. Moral emotions, occupations.

Climates that are moderately cold are more favourable to long life. This observation equally applies to the vegetable kingdom; and trees that have scarcely attained their full growth in northern regions are drooping in the south. There also we find beasts and birds resisting the inclemency of the weather by the thickness of their coats and plumage, or a layer of grease; while many animals burrow in the earth to seek a state of torpor and insensibility, until restored to active life by a more genial temperature. Dryness of soil is another source of health and life; and the hardy mountaineer's existence is seldom abridged by the diseases that visit the inhabitants of damp and swampy regions. Steril plains are more salubrious than regions covered with a rank and exuberant vegetation, or highly cultivated grounds, from many obvious reasons. The humid earth is not turned up, and decayed vegetable substances are not acted upon in a deleterious manner by the solar heat. When we consider the various causes of disease that must abound in crowded and corrupt cities, we might imagine that mortality would be much greater than in the country; yet observation has not proved this difference to be as material as one might expect, at least as regards disease, the sad effects of poverty and starvation not being taken into account. Various reasons may be a.s.signed for this apparent anomaly. In cities a more regular state of excitement prevails, and man's constant occupations scarcely give him time to attend to slight ailments, that, under other circ.u.mstances, might be aggravated.

Moreover, intermittent fevers and visceral affections are more frequent in the country; and cottagers are exposed to more constant damp and severer revolutions in the atmospheric const.i.tution than citizens. The mortality amongst men is greater in cities than in women; the latter do not enjoy so long a life in the country. March and April have been found the most fatal months. They are periods of atmospheric transition from cold to a higher temperature, and must therefore prove trying to the weak and the aged. The end of autumn is also deemed a sickly period; and the equinoxes have ever been considered critical, the solstices much less injurious. In Great Britain and the north-westerly regions of Europe, northerly and easterly winds are more prevalent in March, April, and May, owing, it is supposed, to the currents established to replace the warmer air, as it rises from the surface of the Atlantic and more southerly countries. These winds are generally dry and cold, followed by fogs, and give rise to catarrhs, bronchial and pulmonary affections. It is calculated that in our climes pulmonary affections carry off one-fifth of the population, or 191 in 1000.

In regard to the variety of races, it has been observed that those people who sooner attain p.u.b.escence are the shortest-lived. Precocious excitement must bring on premature old age. Negroes seldom attain an advanced period of life; and the progress of years is more rapidly descried in their features and their form than in Europeans who have migrated to their clime. The negroes of Congo, Mozambique, and Zanguebar, seldom reach their fiftieth year. In northern lat.i.tudes longevity is more frequent: this is observed in Sweden, Russia, Poland, Norway. Some writers have looked upon the established religion of a country as influencing the duration of life; and Toaldo a.s.serted that Christians are shorter-lived than Jews. To this observation it may be remarked, that Jews are in general a very sober, industrious, and active race, circ.u.mstances that must materially tend to prolong their days. Moreover, by their legislation they are very careful in the choice of the meat they consume. In Catholic countries fasting may be taken into calculation, not from the effects of abstemiousness, which would be more favourable to health than injurious, but the sudden return to feasting and gormandizing, by way of revenge, when the fast is over.

Shrove Tuesday and Easter Sunday are noted in red letters in the gastronomic almanac; and the suppers that follow the midnight ma.s.ses of Christmas generally require the apothecary's aid on the following morning.[46]

In regard to conformation, very tall and spare subjects are seldom long-lived; and the same observation applies to the stunted and diminutive. A well-set body, with a broad and deep chest, a neck not over-long, with well-formed and firm muscles, generally hold forth a fair prospect of old age.

Children born before the regular period of gestation, those who have been weaned too early, or given to nurses whose milk was not of a proper quality, are seldom strong. Too rapid a growth will also shorten the s.p.a.ce of existence.

Our avocations and pursuits materially affect health and the consequent duration of life; and the nature of the excitement man is submitted to produces a remarkable effect. It has been calculated in France that one hundred and fifty-two academicians, whose aggregate years were ten thousand five hundred and eleven, averaged sixty-nine years and two months. The following calculation of Madden will further ill.u.s.trate this curious subject.

AGES OF GREAT MEN.

_Natural Philosophers._

Bacon 78 Buffon 81 Copernicus 70 Cuvier 64 Davy 51 Kepler 60 Laplace 77 Leibnitz 70 Newton 84 Whiston 95 Euler 76 Franklin 85 Galileo 78 Halley 86 Herschel 84 Lalande 75 Lewenhoeck 91 Linnaeus 72 Tycho Brahe 75 Wollaston 62

_Poets._

Ariosto 59 Byron 37 Collins 56 Cowper 69 Dryden 70 Gray 57 Milton 66 Pope 56 Spenser 46 Thomson 48 Burns 38 Camoens 55 Cowley 49 Dante 56 Goldsmith 44 Metastasio 84 Petrarch 68 Shenstone 50 Ta.s.so 52 Young 84

_Moral Philosophers._

Bacon 65 Berkeley 79 Condillac 65 Diderot 71 Fitche 52 Helvetius 57 Hume 65 Kaimes 86 Malebranche 77 Stewart 75 Bayle 59 Condorcet 51 Descartes 54 Ferguson 92 Hartley 52 Hobbes 91 Kant 80 Locke 72 Reid 86 St. Lambert 88

_Dramatists._

Alfieri 55 Goethe 82 Marlow 32 Racine 60 Shakspeare 52 Congreve 59 Crebillon 89 Farquhar 30 B. Jonson 63 Moliere 53 Corneille 78 Ma.s.singer 55 Otway 34 Schiller 46 Voltaire 84 Colman 61 c.u.mberland 80 Goldoni 85 De Vega 73 Murphy 78

_Authors on Law and Jurisprudence._

Bentham 85 Butler 83 Erskine 73 Gifford 48 Hale 68 Littleton 75 Montesquieu 66 Romilly 61 Tenterden 78 Vatel 53 Blackstone 57 c.o.ke 85 Filangieri 36 Grotius 63 Holt 68 Mansfield 88 Redesdale 82 Rolle 68 Thurlow 74 Wilmot 83

_Miscellaneous and Novel Writers._

Cervantes 70 Scott 62 Smollett 51 Defoe 70 Richardson 72 Johnson 75 Warton 78 Tickell 54 Bathurst 84 Hawkesworth 59 Le Sage 80 Fielding 47 Rabelais 70 Ratcliffe 60 Sterne 56 Addison 48 Steele 59 Montaigne 60 Thornton 44 Hazlitt 58

_Authors on Revealed Religion._

Baxter 76 J. Butler 60 Calvin 56 Doddridge 54 J. Knox 67 Luther 63 Melancthon 64 Porteus 77 Sherlock 67 Whitefield 56 Bellarmine 84 Bossuet 77 Chillingworth 43 G. Fox 67 Lowth 77 Ma.s.sillon 79 Paley 63 Priestley 71 Wesley 88 Wycliffe 61

_Authors on Natural Religion._

Annet 55 Cardan 75 Sir W. Drummond 68 N. Freret 61 Lord Herbert 68 St. Pierre 77 Tindal 75 Vannini 34 Bolingbroke 79 Chubb 65 Dupuis 67 Gibbon 58 Spinosa 45 Shaftesbury 42 Toland 53 Volney 66

_Medical Authors._

J. Brown 54 Cullen 78 Fordyce 67 Gall 71 Harvey 81 J. Hoffman 83 W. Hunter 66 M. Good 64 Pinel 84 Tissot 70 Corvisart 66 Darwin 72 Fothergill 69 J. Gregory 48 Heberden 92 Hunter 65 Jenner 75 Paracelsus 43 Sydenham 66 T. Willis 54

_Philologists._

Bentley 81 Casaubon 55 Hartzheim 70 Heyne 84 Parr 80 Pighius 84 Raphelengius 59 J. J. Scaliger 69 H. Stephens 71 Vossius 73 Burton 64 Cheke 44 J. Harman 77 Lipsius 60 Pauw 61 Porson 50 Salmatius 66 Sigonius 60 Sylburgius 51 Wolfius 64

_Artists._

Bandinelle 72 Canova 65 Flaxman 71 Giotto 60 San Sovino 91 A. Caracci 49 David 76 Raphael 37 Salvator Rosa 58 P. Veronese 56 Bernini 82 Donatello 83 Ghiberti 64 M. Angelo 96 Verocchico 56 Claude 82 Guido 67 Reynolds 69 t.i.tian 96 West 82

_Musical Composers._

Arne 68 Beethoven 57 Bull 41 Corelli 60 Greby 72 Haydn 77 Kerser 62 Mosart 36 Piccini 71 Scarlatti 78 Bach 66 Burney 88 Cimarosa 41 Gluck 75 Handel 75 Kalkbrenner 51 Martini 78 Paesiello 75 Porpore 78 Weber 40

To this list we may add the following instances of longevity from the late publication of Mr. Farren:

Adling 93 Alc.o.c.k 91 Bernabel 89 Celdara 90 Canpra 84 Casipini 90 Cervetti 101 Child 90 Creighton 97 Eichole 80 Genimani 96 Gibbons 93 Ha.s.se 90 Hempel 86 Hesse 91 Leveridge 90 Lopez 103 Pittoni 90 Reike 100 Sala 99 Sch.e.l.l 87 Schramm 82 Telleman 86 F. Turner 99 W. Turner 88 Wagennell 98

In regard to the mortality of musicians, we give with much pleasure the following extract from the same work:

"The ages of 468 persons at death, were all that could be obtained from a biography of musicians; of these, 109 born since the year 1740 are excluded, because some of their cotemporaries were yet living at the date of such biography, also 41 more are excluded as having died under 50 years of age. There remain then, the ages at death of 318 persons on which the present observation is made.

"From the ages of 50 years to the end of life, the _apparent_ rate of mortality among musicians, appears very nearly with the lowest known rate, or that which prevails in villages, and it is scarcely probable that such rate should so agree without being the true one. For a musician to belong to the last cla.s.s of human life, is very credible, when it is considered that eminence can only be attained by close mental devotion to an exalted science, and unremitting application to its practical acquirement, which abstraction would interrupt and intemperance destroy.

"The mean age of musicians, born _since_ 1690, is 67-3/4 years, or two years greater than those born before 1690, from which it might be conveniently concluded, that the moderns were longer lived than the ancients. The case is precisely the reverse, at least for ages above 50, to which alone the materials are applicable. The expectation of life at the age of 60 of the ancients were nearly 15 years, of the modern musicians 13-1/2. The materials (limited as they are) from which these conclusions are drawn, support the doctrine, that the mortality of the moderns is less at middle, but greater at advanced age, than the mortality of the ancients."

Dr. Caspar, of Berlin, in his late very interesting work on the duration of human life, has given the following conclusions:

Medium longevity.

Clergymen 65 Merchants 62 Clerks 61 Farmers 61 Military men 59 Lawyers 58 Artists 57 Medical men 56

The results of the other cla.s.ses, with respect to their united ages, and the average of each, are--