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

  • John Hunter
Date:
1840
Catalogue details

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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    cupped. On the same day, four ounces of blood were taken from another person's arm, which, on coagulating, showed no inflamma- an animal is frozen or asphyxiated. On the other hand, life is sometimes sud- denly and completely extinguished, without any apparent change having taken place in the organization of the body. On the Life of the Blood.—The difficulty of conceiving that the blood is endowed with life arises merely, as Mr. Hunter observes, from its being a fluid; but we have not the smallest reason for assuming a priori that in the nature of things there is a more intimate connexion between life and a solid than between life and a fluid. Let us, therefore, dismiss this prejudice entirely from our minds, and examine the real grounds on which the doctrine of the life of the blood rests. From many circumstances attending this fluid, it would seem to be the most simple body we know of endowed with the principle of life; consequently we should expect that the proofs of its vitality would be deducible chiefly from the resistance which it offers to external agencies. 1st. If a dead frog or eel be exposed to a freezing mixture, it sinks to 32°, freezes, and continues to fall to the temperature of the mixture. If the animal be alive it will sink to a few degrees below 32°, and remain at that point for a certain time, until the power of resistance be exhausted : it then dies, congeals, and sinks to the temperature of the mixture. If two eggs be similarly treated, one of which has had its powers of resistance destroyed by previous freezing, and the other is fresh, a like result is obtained : the former sinks uninterruptedly to the temperature of the mixture, the latter resists for a time at a few degrees below 32°, then congeals, and becomes cold as the former. If two portions of blood, one of which has been previously frozen and the other not, be exposed in a similar way to a freezing mixture, precisely the same thing occurs. Now are we not justified in concluding that the resistance to cold arises in each instance from the same cause 1 If it is the possession of life which enables the eel and frog to maintain their temperature for a time, it is the possession of life which also enables the fresh egg and the fresh blood in like manner to maintain their temperature. The objection that the resistance in the blood may be merely from a remainder of vital influence imparted to it by the solids, rests on the notion that there is in the nature of things a greater connexion between asolid and life than be- tween a fluid and life: but this is a mere assumption, the contrary of which may be the fact; for in a perfect animal, as the eel or frog, it is not until the fluids viz., the blood, &c, have become frozen that the animal is congealed. A solid deprived of blood is as little able to bear cold as blood separated from the solids. 2d. Parts of animals, such, for example, as the ears of rabbits, and even whole animals, such as several insects in their chrysalis state, admit of being com- pletely frozen without the necessary extinction of life. The blood in the same manner, admits of being frozen without destroying its coagulating property. As, however, the ears of a rabbit become flaccid, so the coagulum of blood which forms after it has been frozen is exceedingly loose. Cold acts as a sedative to the whole system, and if its action is sufficiently prolonged extinguishes life; but its action on the coagulation of the blood is precisely analogous, re- tarding or altogether preventing this act, in proportion to its intensity and con- tinuance. 3d. In all vegetables and animals, particularly those which are high in the zoological scale, there is a disposition to maintain a uniform temperature. Thus blood taken from the arm in the most intense cold that the human body can bear, raises the thermometer to the same [or nearly the same] height as blood taken in the most sultry heat. Thus also fresh blood is slower in parting with its heat than other fluids of a similar consistency and specific gravity, even before coagulation. 4th. The analogy of heat is not so well marked as that of cold, yet the blood resists any considerable increase of temperature, which is seldom found to ex- ceed by more than 3° or 4° that of the standard. Again, Heat has the power of exciting action in an animal; and we find that heat even increases the action