Review of Dr. Caldwell's pamphlet : entitled Physiology vindicated, in a critique on Liebig's Animal chemistry / by Robert Peter.

  • Peter, Robert, 1805-1894.
Date:
1843
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Licence: Public Domain Mark

Credit: Review of Dr. Caldwell's pamphlet : entitled Physiology vindicated, in a critique on Liebig's Animal chemistry / by Robert Peter. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    Take your tubful of hot water. Immerse in it a large thermometer; marking first the height of the mercury ; allow it to remain immersed, but at rest, for one minute; —observe, then, how much the column has risen. Now move it about forcibly in the water; immersed to the same depth, for the space of another minute ; and if the mercury does not expand greatly more, in equal times, while the instrument is in motion than while at rest, I will not only believe in nature's horror of a vacuum, but in all the dogmas that have ever been propounded. The simple truth is, that hot fluids part with their heat more rapidly when they impinge, in a current on the body to be heated, than they do when at rest; —and the true reason why the water felt hotter, to the limbs im- mersed in it, when it was agitated than when it was in a state of rest, was. that it gave them more heat in a given time. But the Doctor says «the leg has cooled the water to some distance around it!! Shade of Rumford! Can it be believed that a learned professor, in the middle of the nineteenth century, should know so little of the currents which exist in heating and cooling fluids, or hydrostatics, as to suppose, that a hollow column of cold water, extending to the dis- tance of some inches, could forget its specific gravity so far. as to stand up, and maintain its place around the leg, although surrounded on all sides by hotter, and specifically lighter water! If this is true, the wonderful vital principle — the mysterious consti- tutional instinct — not only masters and destroys chemical and physical forces within the body; but its power is even extended to some inches be- yond it!! We leave the doctor to decide whether this proves too much, or nothing at all, or both. The living member does cool the water, however, and much more rap- idly than is in proportion to its rise of temperature. But the particles of water, which lose their heat by contact with the leg, becoming more con- tracted and therefore heavier, by cooling, immediately fall in a current to the bottom of the fluid, giving place to other and warmer particles. A process which continues as long as the cooling takes place, and without which it would not be easy either to heat or cool water. In order that he may understand how the members may cool the water, without being themselves heated in a proportionate degree; or how a dead; limb is heated, under these circumstances, more than a living one, I will propose to the professor other interesting experiments; — which, if he is desirous of finding truth, he will perform: —