Licence: Public Domain Mark
Credit: Misconceptions regarding arterial elasticity / by G. A. Gibson. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
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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 insufliciency 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 wiM 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, distensile pulse and a sohYEmographic 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 nroduced, but solely by the amount of resistance to stress. As we have already seen. Professor Koy and other workers in this lield correctly measure elasticity by the amount ot dis- tortion which can be undergone, followed by return to normal form; and how a soft, distensile pulse and a sphygmo- craphic tracing with a very high dicrotic rise can be pro- duced by a diminution of the elasticity of the art^ies entirely passes my comprehension. Again, let us hear Pro- fessor Tlmma. “ Lastly,” he says, “ I may point out that in many cases the appearance of a pulse in the retinal on ophthalmoscopic examination is *0 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 we compare the first passage referred to with ]ust 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 eSSifies tlm point made out by Roy, previously referred](https://iiif.wellcomecollection.org/image/b21939287_0012.jp2/full/800%2C/0/default.jpg)
