The elastic properties of the arterial wall / by Charles S. Roy.

  • Roy Charles S. (Charles Smart)
Date:
1880
Catalogue details

Licence: Public Domain Mark

Credit: The elastic properties of the arterial wall / by Charles S. Roy. 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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    curves. The vertical lines, placed 1 centimeter apart, are curved, and their curvature is that of a circle whose radius has the same length as the lever employed. They give, therefore, the correction necessitated by the fact that the lever-point does not describe a straight vertical line. The horizontal lines are 5 mm. apart, and, since the variations in length of the strips examined were magnified five times by means of the lever, the intervals between these lines are equivalent to 1 mm. of the length of the strip. In all of the curves on PL VII. the elongations of the strips were magnified five times by the lever. The initial length of the strips taken was not the same for the different figures, but varied according as the aorta examined was found to be more or less elastic. Fig. 12 is from the aorta thoracica descendens of a female child, set. 2^ years. Death caused by diphtheritis, complicated by broncho-pneumonia. No emaciation. Circumference of aorta beyond arch = 23 mm. Fig. 13 is from a female, set. 22. Death due to septic poisoning after child-bed. Curves are from aorta thoracica descendens, the circum- ference of the vessel at that part being 45 mm. Fig. 14 is from a male, set. 26, who succumbed to a rapidly fatal pneumonia. Circumference of aorta at part taken, viz., middle of thoracic portion, was 50 mm. In none of these three cases was there any appearance of disease affecting the aorta. They resemble, moreover, very closely the curves which are obtained with the same instrument from the aorta of the dog, cat, or sheep. They are, then, the curves given by healthy aortas. In all of them it can be seen that the longitudinal strip expands with light weights more readily than the transverse strip, but that with heavier Weights this relation is reversed, and the curves cut one another. For example, in Fig. 12, with weights below 90 grammes, the longitudinal strip was longer than the transverse, while with weights above 90 grammes the reverse was the case. The curves of longitudinal elasticity of strips of aorta taken trans- versely and longitudinally do not always cut one another. Exceptions occur even with perfectly healthy vessels. Of this an example can be seen in Fig. 17, which is from the aorta of a female child, aged 9 years. Broncho-pneumonia was the cause of death, the aorta being to all appear- ance perfectly healthy. In this tracing the upper of the four curves is from a transverse strip, and the third (counting from above) from a longitudinal. In this case, it can be seen, that with light weights, the longitudinal is more expansible than the transverse, and that this relation