Theory of Circulation by Respiration Synopsis of its Principles and History

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SECTION I.

First step in the discovery—Animal Heat the product of Respiration. Second step—Heat evolved in the lungs by Respiration there produces Expansion. Third step—Expansion; implied motion, which from the organism must conduct the blood to the left ventricle of the Heart. Theory imperfect, until the formation of sufficient vapor or steam in the lungs is perceived and acknowledged.

To Dr. Marcy.—In complying with your request to write for your journal an article embodying my theory of the motive powers which produce the circulation of the blood, together with some account of its rise and progress, I obey what I regard as a call of duty; and thus requested, do it with pleasure.

But my theory, with its history, cannot thus be written without egotism. Logicians say, that the way to convince others is to retrace, in order, the steps by which you yourself became convinced, which is to be egotistic. But in this case, there is a further reason: the scientific discoverer must speak of the apparatus by which he experiments, and mine was often my own physical frame.

Twenty years ago, while yet my mind, laboring with this great subject, was condemned

“to drudge
Without a second and without a judge,”

you, sir, comprehended the hypothesis which has now become a theory, and you waited not for others to speak, but you fully acknowledged its truth; and although, in Hartford, as now in New-York, you were thronged with practice, (then allopathic), you yet found time to furnish me with added experiments, made in your office, confirmatory of its truth, which by your permission were afterwards added in your name to my published work.

The first step in the theory occurred to my mind in the winter of 1822, and while I was engaged in founding the Troy Female Seminary. Being in attendance on a course of lectures on chemistry, and at the same time teaching to a class Mrs. Marcett’s excellent work on that subject, one cold morning, as I was walking briskly up a hill, I said to myself, Why do I grow warm? Whence comes this accession of caloric? It cannot be transmitted to me from any object without, because every thing which comes in contact with me is cold. Snow is under my feet, and frosty air surrounds me; and, as to clothing, even the softest furs impart no warmth—they but keep from escaping that which comes from within. What other method besides transmission is there of gaining heat? There is the elimination of caloric, when, in substances chemically combining, weight is gained and bulk is lost. Is there any such combination going on in me? Yes; this atmospheric air, when I inspire it, has oxygen combined with nitrogen; but when I expire, the oxygen has disappeared, and heavier substances—carbonic acid gas and watery vapor—are returned in its place. Thus, it must be, animal heat is evolved. It is the product of respiration; and it is because I breathe faster and deeper, that more carbon is oxidized or burned, and more heat is set free in my lungs; and therefore I grow warm as I walk up this hill, though all around me is cold.

The mind, excited by new and great thoughts, works with unwonted energy; and mine at once collected so many proofs, that I became perfectly convinced of the truth of the hypothesis....