First principles of medicine / By Archibald Billing.

  • Archibald Billing
Date:
1831
Catalogue details

Licence: Public Domain Mark

Credit: First principles of medicine / By Archibald Billing. Source: Wellcome Collection.

    19/142 (page 11)
    i! the tube, whilst they reszs¢ its dilatation. Now it may be thought that the movements of arteries seen at the wrist and in the temples is their dilatation, but it is the serpentine motion caused by the alteration of the curve, the artery being elongated at each injection from the heart. Where the artery is perfectly straight you may lay it bare and scarcely see it move, but the moment you compress it with the finger, or tie a ligature around it, you perceive it pushed at every pulse. To illustrate the deception of the sensation which the pulse gives, as if the artery were dilated at each beat; if a long vein removed from the body have a syringe adapted to one end, the other being raised, or arranged with a spring valve, which yields to the jets so as to keep it full, and fluid be sent through in jets, it will upon pressure by the finger, give the sensation of dilatation, but the eye perceives none: again, if any one grasp the leather tube of a fire or garden engine, the sensation given, will be that of its expanding in the hand at each stroke of the pump, but the eye contradicts the sensation, it is merely the tendency to resume the cylindrical form from the outward pressure of the fluid, but not expansion. It has been attempted to be proved that the heart has an aciive power of dilatation,* by which it helps to * The ‘‘impulsion”’ of the heart against the side (which takes place between the first and second sound, that is. just as the auricles have filled the ventricles, and the latter become rigid commencing their contraction), isin proportion to its muscular action, and is pro- duced by the heart assuming a form more approaching to the globular, aud becoming firm at the same time, as when the gastrocnemii muscles act; the heart being in an angle between the diaphragm and parietes of the chest, the increase of its transverse dimensions has the effect of