There is certainly one limit which the increase of no organic being can exceed: the limit of the necessary means of subsistence. But, so far as the human race is concerned, this notion is somewhat more extensive, inasmuch as it embraces besides food, also clothing, shelter, fuel, and a great many other goods which are not, indeed, necessary to life, but which are so considered.[239-1] We may illustrate the matter by a simple example in the rule of division. If we take the aggregate of the means of subsistence as a dividend, the number of mankind as divisor; then the average share of each is the quotient. Where two of these quantities are given, the third may be found. Only when the dividend has largely increased can the divisor and quotient increase at the same time (prosperous increase of population). If, however, the quotient remains unchanged, the increase of the divisor can take place only at the expense of the quotient (proletarian increase of population).[239-2] Hence it is to be expected that the quantity of the means of subsistence being given and also the requirement of each individual, the number of births and the number of deaths should condition each other. Where, for instance, the number of church livings has not been increased, only as many candidates can marry as clergymen who held such livings have died. The greater the average age of the latter is, the later do the former marry, in the average, and vice versa. And so, in the case of whole nations, when their economic consumption and production remain unaltered.[239-3] A basin entirely filled with water can be made to contain more only in case it is either increased itself, or a means is found to compress its contents. Otherwise as much must flow out on the one side as is poured in on the other.
And so, everything else remaining stationary, the fruitfulness of marriages must, at least in the long run, be in the inverse ratio of their frequency. (See § 247.)[239-4] [239-5]
[239-1] When it is known that, in the Hebrides, one-third of all the labor of the people has to be employed in procuring combustible material (McCulloch, Statist. Account, I, 319), it will no longer excite surprise that, according to Scotch statistics, some parishes increase in population after coal has been found in them, and others decrease when their turf-beds are exhausted.
[239-2] Compare Isaias, 9:3. According to Courcelle-Seneuil, Traité théorique et pratique d'Economie politique, I, 1858, the chiffre nécessaire de la population égal à la somme des revenus de la société[TN 64] diminuée de la somme des inégalités de consommation et divisée[TN 65] par le minimum de consommation: P=(R-J)/M.
[239-3] Thus Süssmilch, Göttliche Ordnung in den Veränderungen des menschlichen Geschlechts, 1st ed., 1742, 4th ed., 1775, I, 126 ff., assumes that one marriage a year takes place, on from every 107 to every 113 persons living. On the other hand, 22 Dutch towns gave an average of 1 in every 64. This abnormal proportion is very correctly ascribed by Malthus, Principles of Population, II, ch. 4, to the great mortality of those towns: viz., a death for every 22 or 23 persons living, while the average is 1:36. The Swiss, Müret, (in the Mémoires de la Société économique de Berne, 1766, I, 15 ff.), could not help wondering that the villages with the largest average duration of life should be those in which there were fewest births. "So much life-power and yet so few procreative resources!" Here too, Malthus, II, ch. 5, solved the enigma. The question was concerned with Alpine villages with an almost stationary cow-herd business: no one married until one cow-herd cottage had become free; and precisely because the tenants lived so long, the new comers obtained their places so late. Compare d'Ivernois, Enquête[TN 66] sur les Causes patentes et occultes[TN 67] de la faible Proportion de Naissances à Montreux: yearly 1:46, of the persons living, while the average in all Switzerland was 1:28.
In France according to Quételet, Sur l'Homme, 1835, I, 83 ff., there was:
| In number of Departments | One marriage a year for every | Children to a marriage | One death yearly for every | ||
| 4 | 110-120 | inhabitants | 3.79 | 35.4 | inhabitants |
| 15 | 120-130 | " | 3.79 | 39.2 | " |
| 23 | 130-140 | " | 4.17 | 39.0 | " |
| 18 | 140-150 | " | 4.36 | 40.6 | " |
| 10 | 150-160 | " | 4.43 | 40.3 | " |
| 9 | 160-170 | " | 4.48 | 42.7 | " |
| 6 | 170 and more | " | 4.48 | 46.4 | " |
The two departments of Orne and Finisterre present a very glaring contrast: in the former, one birth per annum on every 44.8 (1851 = 51.6), a marriage on every 147.5, a death on every 52.4 (1851 = 54.1) living persons; in the latter, on the contrary, on every 26 (1851 = 29.8), 113.9 and 30.4 (1851 = 34.2). In Namur, the proportions were 30.1, 141, 51.8; in Zeeland, 21.9, 113.2, 28.5. (Quételet, I, 142.) The Mexican province, Guanaxuato, presents the most frightful extreme: one birth per annum on every 16.08 of the population living, and one death in every 19.7. (Quételet, I, 110.)
[239-4] Compare even Steuart, Principles, I, ch. 13. Sadler, Law of Population, 1830, II, 514:
| Marriages per annum on every 10,000 inhabitants | Children on every 100 Marriages | ||
| [239-5] | In the purely Flemish provinces of Belgium | 128 | 481 |
| In the purely Wallonic provinces of Belgium | 139 | 448 | |
| In the mixed provinces of Belgium | 152 | 425 | |
| In Holland | 148 | 476 | |
| In Lombardy | 166 | 489 | |
| In Bohemia | 173 | 413 | |
| In the kingdom of Saxony | 170 | 410 |