An experimental inquiry into the pathology and treatment of asphyxia ... To which the Royal Humane Society awarded the Fothergillian Gold Medal / [John Eric Erichsen].

  • Erichsen, John Eric, 1818-1896.
Date:
1845
Catalogue details

Licence: Public Domain Mark

Credit: An experimental inquiry into the pathology and treatment of asphyxia ... To which the Royal Humane Society awarded the Fothergillian Gold Medal / [John Eric Erichsen]. Source: Wellcome Collection.

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    colouration of the blood ; 5. Permeation of fibres of the heart with black blood; 6. Weakening and cessation of the action of these fibres*. Now, in Dr. Alison’s experiment, supposing that the chest were laid open and the heart exposed as rapidly as possible after the death of the animal, at the very least a minute or a minute and a half must have elapsed, after the cessation of the respiratory movements, before this could be accomplished, during which the heart would be acting strongly, and sufficient time would elapse for the circulation to make at least one or two circuits. Blood would consequently, as in all cases of asphyxia, from whatever cause, accumulate in the right cavities of the heart. As an accumulation of blood in these cavities is therefore a necessary w result of the sudden annihilation of the functions of the brain, in consequence of the suspension of the respiratory movements or of the chemical chancres in the lungs—one or both—when the animal has, up to the moment of its death, been breathing atmospheric air, the same phenomenon ought not, I think, to be adduced as an effect of the cessation of the chemical changes alone, when it is met with in an animal that is killed whilst breathing nitrogen,—there being no evidence that it existed before the death of the animal, and that it did * not result from the continuance of the circulation after the cessation of the respiratory movements. It was thought that the relative influence of the arrest of the respiratory movements, and of the cessation of the chemical changes in occasioning an accumulation of blood in the cavities of the heart, might be more accurately determined by keeping up the movements of respiration, not only until after these changes had been arrested, but until the pulsations of the heart and the circulation of the blood had entirely ceased ; the difference in the proportional quantity of blood contained in the two sides of the heart in this, and in ordinary cases of asphyxia, being the measure of the relative influence of the cessation of the chemical changes, and of the arrest of the respiratory move¬ ments. The following experiment was accordingly performed :— Exp. 1. A tube having been introduced into the trachea of a small black terrier, a syringe capable of holding eight ounces, and filled with air, was attached to it. The piston was then worked in such a way that the natural movements of respiration might be imitated. I2 minute.—Animal began to struggle. 3d minute.—All struggles ceased. 1 Ith minute.—The chest was laid open, and the lungs found fully distended and of a darkish grey colour. 14th minute.—Heart's action ceased entirely. During the whole of this time the action of the syringe had been continued except whilst the chest was being laid open, which renders the experiment perhaps a little less conclusive than it otherwise would have been. * Koclu'rchos Phvsiologiques, ]>. 320.