Page:Popular Science Monthly Volume 25.djvu/692

676 larger than those of the rich. And it is equally certain that brain-workers have, ordinarily, smaller families than muscle-workers. The industrial classes of our day do not perform exhaustive labor. Nor are they usually in the habit of strong mental exercise. The physical labor they perform seems to have no limiting effect upon their procreative powers. The families of day-laborers are usually above the average in number. And it has been observed that the pioneer inhabitants of a new country are very prolific. While physical assault upon Nature is the rule, with food abundant and easily obtained, the physiological check upon increase does not seem to strongly operate. When this first severe duty is over, and men settle down to a mental assault upon Nature, their fecundity considerably decreases. The extensive families of the pioneer settlers of this country are being replaced by the small families of the active brain-workers among their posterity.

As to whether animals that depend mainly on shrewdness are less prolific than those that trust chiefly to strength and agility, we have not sufficient facts at hand to decide. Among the lower human races there is a marked chastity and infertility in the hunter and pastoral as compared with the agricultural tribes. But the former pass lives of much greater mental excitement than the latter. The steady, regular labor of the agriculturist is replaced in the nomad by rapid variations from excessive exertion to extreme inactivity, while a constant exercise of cunning and shrewdness is necessary in the rapidly fluctuating perils and difficulties of the nomadic life.

As to the relations existing between the various classes in civilized nations, it may be mentioned that the population of country districts appears, as a rule, to be more prolific than that of cities. Until within a recent period there was hardly one of the large cities of Europe that kept up its population by the natural increase of its inhabitants. Their increasing numbers were due to continual supplies from the rural districts. The much greater mental activity of civic populations as compared with those of the country is, at least, significant in this connection. If, again, we consider the higher classes in civilized nations, it at once appears that there is a constant tendency to decrease of population in these classes, and a necessity of frequent replacement from the lower grades of society. Thus there has been, in every century, a rapid thinning out of the families in the British peerage. An incessant creation of new peers has taken place, and yet they have hardly kept up their numbers, while very few of the original noble families have an existing representative. The same thing appears in the history of ancient Rome. The early noble families were almost extinct in the time of Claudian. Those created in the reigns of Cæsar and Augustus were nearly exhausted at the period of Tacitus. Malthus says that, in the town of Berne, of 487 wealthy families, 379 became extinct in two centuries. In 1623 the sovereign council was composed