A treatise on the blood, inflammation, and gun-shot wounds / by John Hunter ; with notes by James F. Palmer.

  • John Hunter
Date:
1840
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Licence: Public Domain Mark

Credit: A treatise on the blood, inflammation, and gun-shot wounds / by John Hunter ; with notes by James F. Palmer. 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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    lated thermometers, one in each cup of blood, I observed which cooled first, for I did not expect so much heat to be produced in the second as to make it warmer, but conceived, if any heat was formed, it would retard the cooling of the fresh blood; but it rather cooled faster, which I imputed to the coagulated blood parting with its heat slower than the fluid blood. These experiments I have repeated several times, with nearly the same effect. I then con- ceived the experiment would be more conclusive if I could get blood in a fluid state which was naturally of the heat of the atmo- sphere, for which purpose I took the blood of turtles. A healthy turtle was kept in a room all night, the floor of which was about 64° and the atmosphere 65°. In the morning the heat was nearly the same. The thermometer was introduced into the anus, and the heat of that part was 64°. The animal being sus- pended by the hind legs, the head was cut off at once, and the blood caught in a basin; the blood while flowing was 65°, and when collected was 66°, but fell to 65° while coagulating, which it did very slowly: it remained at 65°, and when coagulated was still 65°. These experiments had been made several times, but not with that nice accuracy which was obtained by causing all the heats to correspond exactly; yet, as they were all known and marked down, if any heat had been produced upon coagulation its exact quantity would have been ascertained in each; and, indeed, in some it seemed to cool, but in none it became warmer. From these experiments, I should say that in the coagulation of the blood no heat is formed.* Coagulated blood is an inorganized animal substance. When the blood is thinly spread before coagulation, or oozes out on sur- faces, (in which act it immediately coagulates,) and coagulates in that form, it may then be said to form an inorganized membrane, of which there are many: and organization is seemingly so simple in many (which we know to be constituent parts of the body), that * [The change in the capacity of bodies for heat depends on the change of their densities; but no change takes place in the sum of the densities cf the con- stituents of the blood during, or as the effect of, coagulation, for what the fibrin gains in specific weight is exactly balanced by what is lost by the serum ; and. were this otherwise, we should still not expect any appreciable degree of heat to be evolved, when we reflect on the extremely small proportion which the fibrin bears to the whole mass of the blood, and that it is this principle alone which un- dergoes coagulation. The opinion in the text has, nevertheless, been controverted by several experimentalists. Fourcroy, in one instance, observed the heat to rise during coagulation from 20° to 25° Cent., or nearly 11° Fahr. {.inn.de Chimie, vii. 147.) Dr. Gordon also, in some experiments, estimated the rise to be as much as from 6° to 12°. {Jinn, of Phil., iv. 139.) And Dr. Scudamore was led to a similar conclusion, viz., that a slight evolution of heat takes place during the coagulation of the blood. {Op. cit., p. 75.) I am of opinion, however, that the experiments of Davy on the blood of sharks and turtles, and those of Thack- rah on warm-blooded animals, are more to be depended on, and these fully con- firm the accuracy of Mr. Hunter's observations. {Thackrah, p. 60.) Raspail has even gone into the opposite opinion, and imagined that the temperature of the blood is actuallv reduced by the act of coagulation. {Syst. Chim. Org., p. 361.)]