PRINCIPLE OF POPULATION.
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point of magnitude, at which they would not arrive. In all these cases therefore, a careful distinction should be made, between an unlimited progress, and a progress where the limit is merely undefined.
It will be said, perhaps, that the reason why plants and animals cannot increase indefinitely in size, is, that they would fall by their own weight. I answer, how do we know this but from experience? from experience of the degree of strength with which these bodies are formed. I know that a carnation, long before it reached the size of a cabbage, would not be supported by its stalk; but I only know this from my experience of the weakness, and want of tenacity in the materials of a carnation stalk. There are many substances in na-
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