men had been shipped from Europe to the North American continent, there would now be no more bears than in the time of Columbus, and possibly fewer, for bear food would not have been increased nor the conditions of bear life extended, by the bear immigration, but probably the reverse. But within the limits of the United States alone, there are now forty-five millions of men where then there were only a few hundred thousand, and yet there is now within that territory much more food per capita for the forty-five millions than there was then for the few hundred thousand. It is not the increase of food that has caused this increase of men; but the increase of men that has brought about the increase of food. There is more food, simply because there are more men.
Here is a difference between the animal and the man. Both the jay-hawk and the man eat chickens, but the more jay-hawks the fewer chickens, while the more men the more chickens. Both the seal and the man eat salmon, but when a seal takes a salmon there is a salmon the less, and were seals to increase past a certain point salmon must diminish; while by placing the spawn of the salmon under favorable conditions man can so increase the number of salmon as to more than make up for all he may take, and thus, no matter how much men may increase, their increase need never outrun the supply of salmon.
In short, while all through the vegetable and animal kingdoms the limit of subsistence is independent of the thing subsisted, with man the limit of subsistence is, within the final limits of earth, air, water, and sunshine, dependent upon man himself. And this being the case, the analogy which it is sought to draw between the lower forms of life and man manifestly fails. While vegetables and animals do press against the limits of subsistence, man cannot press against the limits of his subsistence until the limits of the globe are reached. Observe, this is not merely true of the whole, but of all the parts. As we cannot reduce the level of the smallest bay or harbor without reducing the level not merely of the ocean with which it communicates,