Page:Two Lectures on the Checks to Population.pdf/16

10 instruments of death, not peculiarly appropriated to its own department. Then the view of the subject would be comparatively simple, and we might draw a hard line of distinction between the different checks, separating them into two classes, and placing on one side of the line all those motives, and all those diseases and other causes, which diminish fecundity or destroy life, and which arise from a scarcity of the means of subsistence; and on the other, all causes productive of the same effect, but originating in moral and physical circumstances totally independent of this scarcity. Now, though in the natural course of events, causes appertaining to both of these classes are commonly intermixed in their operation, and cannot be disentangled, and though, perhaps, scarcely a single case of diminished fecundity or of death, in which poverty is concerned, be the result of poverty alone, yet these circumstances constitute no objection to our distinguishing in imagination the quantities of the effects due to each description of causes. A line, or the equivalent of a line, parting the quantities of the effects, must exist in nature, though not visible to the