Volume 1

The practice of medicine / by Thomas Hawkes Tanner.

  • Thomas Hawkes Tanner
Date:
1875
Catalogue details

Licence: Public Domain Mark

Credit: The practice of medicine / by Thomas Hawkes Tanner. Source: Wellcome Collection.

    34/692 (page 6)
    phrenic and intercostal nerves, or disease of the respiratory tract in the cord, obstruction of the larynx by false membranes, many diseases of the lungs, and so on. Secondly, thfere is death by coma, in which the muscular movements required for respiration cease, owing to insensibility produced by certain poisons or by cerebral mischief j examples of which form are seen in many affections of the brain. Thus in death by apncea we have succes- sively impeded respiration, the circulation of venous blood, and in- sensibility ; while in coma the order of the phenomena is reversed, and we find insensibility, cessation of the thoracic movements, and a stoppage of the chemical functions of the lungs. Death from disease cannot by any means always be referred strictly to one or other of these modes : for example, in fevers the impure and disintegrated blood may at the same time cause coma, from its influence on the brain, and asthenia from its want of due nutrient qualities; and again, in some affections of the lungs, apncea and asthenia may equally contribute to the fatal result. If we take death to be the cessation of the circulation, the initial cause is thus seen to be capable of being referred— 1. To the nervous system ; [a), by arrest of the movements of the heart; [b], by arrest of the movements of respiration; sud- denly, as in injury or disease of the medulla, &c.; or slowly, as in coma. 2. To the heart and vessels. 3. To the lungs and respiratory passages. 4. To the blood itself. When the blood is fresh drawn from the body, it forms, in about ten minutes, a gelatinous mass; this singular alteration being due entirely to the separation in the form of delicate fila- ments of the minute proportion of fibrin dissolved in the plasma. In some fifteen minutes, when the process cf solidification is com- plete, the glutinous mass will be found to be shrinking and resolving itself into two distinct portions; which are known respectively as the crassamentum or clot, and serum. This shrinking is due to the further coagulation or contraction of the fibrin; and it continues for some thirty or forty hours, after which tiine no more serum is expressed. The clot consists, then, of the fibrin holding the red corpuscles entangled within the meshes it has formed. These corpuscles will either be equally diffused through the clot; or they may, by sinking from its surface, leave the upper part colourless. Where the latter happens, the colourless layer of fibrin, not being encumbered with corpuscles, contracts more than the lower part, and causes the surface to become concave; and under these two circumstances the clot is said to be buffed^ and cupped.'^ The serum is the liquor sanguinis minus the fibrin; and consequently there is a most important distinction to bo drawn between the plasma of living blood—so to speak, and the