676 TEE POPULAR SCIENCE MONTHLY. 



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 pro- 

 creative powers. The families of day-laborers are usually above the 

 average in number. And it has been observed that the pioneer in- 

 habitants 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 ex- 

 tensive families of the pioneer settlers of this country are being re- 

 placed 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 exer- 

 cise 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 dis- 

 tricts. The much greater mental activity of civic populations as com- 

 pared with those of the country is, at least, significant in this connec- 

 tion. If, again, we consider the higher classes in civilized nations, it 

 at once appears that there is a constant tendency to decrease of popu- 

 lation 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 inces- 

 sant 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 fching appears in the his- 

 tory of ancient Rome. The early noble families were almost extinct 

 in the time of Claudian. Those created in the reigns of Caesar 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 



