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hausted matter are cast into the air. From the lungs and organs of respiration of each one of you here present, there are thrown off nearly 1000 lbs. per annum of what to each has been flesh and blood. Imagine, then, the quantity from the whole animal kingdom, including every living creature, from the smallest insect up to lordly man; and yet this thin air, which receives it all and is never surcharged, is to the earth in extent but as the down to the peach.
By the action of light upon this ejected matter it is decomposed, and resolved into gaseous substances, which enter largely into the components of trees, plants, and vegetables, constituting in them the nutritious parts of animal food. We hunger, and take for nourishment this same carbon again into the stomach, there elaborate it into flesh and blood, and again, with every breath, after it has performed its office and expended its vitality, cast it forth, like the exhausted steam of an engine, into the atmosphere, where it is again, in never ceasing round, filtered through the vegetable process, and re-adapted for animal use.
This flesh and blood, which I call mine, has passed this round—the animal, the inorganic, the vegetable—and been renewed upon me a hundred times since I came into the world.
What a sewer and laboratory may we now see in the atmosphere, by taking into the view the myriads upon myriads of moving things that cast out their dead matter into it. Yet notwithstanding the extent of the operation, the ages that it has been going on, the two parts—the animal which corrupts, and the vegetable which purifies—are so beautifully adjusted and arranged, so wonderfully compensated and balanced, that the nicest analysis can detect in the atmosphere not the slightest change as to its components or their
