Misconceptions regarding arterial elasticity / by G.A. Gibson.

  • George Alexander Gibson
Date:
[1896]
Catalogue details

Licence: Public Domain Mark

Credit: Misconceptions regarding arterial elasticity / by G.A. Gibson. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

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    of the artery now flows in a channel, the wall of which possesses more or less the properties of a rigid tube. This involves an increase of the resistance to the stream which must not be undervalued. The heart is at first able to overcome this by strengthening its contraction. Gradually the thickness of the wall of the left ventricle becomes considerably increased, but the increased activity required of the heart exposes it to the danger of insufficiency of its action. This in many cases leads to a fatal termination.” In the passage just quoted there are many contradictory statements which seem to indicate some deplorable miscon- ceptions, and lest it might be thought that my friend and colleague, Dr. Bruce, is in any degree responsible for the singular confusion of ideas pervading the passage, it is only right to say that his translation has been executed with a fidelity worthy of a better cause. “ During life,” says Pro- fessor Thoma, “the diminution of the elasticity of the arteries shows itself by a soft, d is tensile pulse and a sphygmographic tracing with a very high dicrotic rise, which is unduly far removed from the apex of the wave. The distance of the apex of the dicrotic rise from that of the pulse wave indicates in these conditions that the pulse wave is somewhat slowly propagated in the blood stream.” Such a statement as this deserves the closest examina- tion. It seems as if the author judged elasticity, not by the amount of strain which can be borne and restitution pressure produced, but solely by the amount of resistance to stress. As we have already seen, Professor Roy and other workers in this field correctly measure elasticity by the amount of dis- tortion which can be undergone, followed by return to normal form ; and how a soft, distensile pulse and a sphygmo- graphic tracing with a very high dicrotic rise can be pro- duced by a diminution of the elasticity of the arteries entirely passes my comprehension. Again, let us hear Pro- fessor Thoma. “ Lastly,” he says, “ I may point out that in many cases the appearance of a pulse in the retinal arteries on ophthalmoscopic examination is to be ascribed to a diminution of the elasticity of their wall.” Here the author is on safer ground, but he happens to have crossed to the other side of the hedge from that on which he stood when we compare the first passage referred to with that just quoted. The appearance of a pulse in the retinal arteries shows that the arterial system is either somewhat like a system of rigid tubes with an intermittent flow, or it exemplifies the point made out by Roy, previously referred
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