You see, then, how important the principle of population is.
Malthus has reduced the principle to this formula: [p402]
Population has a tendency to keep on a level with the means of subsistence.
I cannot help remarking in passing that it is surprising that the honour and responsibility of enunciating this principle, be it true or false, should have been ascribed to Malthus. No writer on such subjects since the days of Aristotle but has proclaimed it, and frequently in the very same words.[86]
It is impossible to look around us on the aggregate of animated beings without being convinced beyond doubt that nature has been more engrossed with the care of species than of individuals.
The precautions which nature has taken to ensure the perpetuity of races are remarkable; and among these precautions, a very noticeable one is the profusion of germs or seeds. This superabundance appears to be calculated in an inverse ratio to the sensibility, intelligence, and power with which each species is endowed, to enable it to resist destruction.
Thus, in the vegetable kingdom, the means of reproduction, by seeds, cuttings, etc., which a single plant can furnish, are countless. One elm (were all its seeds to take root) might give birth in a single year to a million of trees. Why should this not actually happen? Because all the seeds have not the benefit of the conditions which vegetable life exacts, namely, space and nourishment. They are destroyed; and as plants are destitute of sensibility, nature has spared neither the means of reproduction nor those of destruction.
Animals, too, whose life is of a type akin to vegetable life, reproduce themselves in immense numbers. Who has not wondered that oysters, for instance, could multiply sufficiently to supply the enormous consumption of them?
As we advance in the scale of animal life, we find that the means of reproduction has been bestowed by nature with greater parsimony.
Vertebrated animals, especially the larger species, do not multiply so quickly as others. The cow goes nine months, produces only [p403] one calf, and must suckle it for some time. Yet even among cattle the reproductive power surpasses what might be thought absolutely necessary. In rich countries, such as England, France, and Switzerland, the number of animals of this description increases notwithstanding the enormous destruction of them; and had we boundless pastures and prairies, there can be no doubt that we might have both a still greater destruction and more rapid reproduction of them. I should say that if nourishment and space were not limited, we might have in a few years ten times more oxen and cows, even if we consumed ten times more meat. The reproductive power of cattle, then, even laying aside the extraneous consideration of the limitation of space and nourishment, is far from being fully developed.