A simple mode of demonstrating how the form of the thorax is partly determined by gravitation / by T.P. Anderson Stuart.; communicated by Professor Schäfer ; received January 12, 1891.

  • Anderson Stuart, Thomas Peter, 1856-1920.
Date:
[1891]
Catalogue details

Licence: Public Domain Mark

Credit: A simple mode of demonstrating how the form of the thorax is partly determined by gravitation / by T.P. Anderson Stuart.; communicated by Professor Schäfer ; received January 12, 1891. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    \_Froin the Qfl// -ef/(frn/’d ^00107^ / yy7f’>7 •'y?/d. “A simple Mode of Demonstrating how the Form of the Thorax is partly determined by Gravitation.” By T. P. Anderson Stuart, M.D., Professor of Physiology in the University of Sydney, N.S.W. Communicated by Professor Schafer, F.R.S. Received January 12, 1891. iK I It is a well-known fact that the quadrupeds have the transverse section of the thorax elliptical with the long axis vertical. This form of thorax, more or less, is possessed also by the human foetus. As the erect posture is gradually assumed in the development of species and of the human individual the ventro-dorsal and transverse diameters approximate to each other, and then, the process continuing, in the adult the transverse diameter exceeds the antero-posterior. That these are the forms proper to the thorax when under the influence of gravitation alone is seen by holding a hoop made of a strip of ordinary crinoline steel ^ inch wide and about 6 feet long, so that its plane is vertical; its form is that of an ellipse. Now grasp the hoop flrmly between the fore-finger and thumb of one hand, and gi’adually turn the internal face of the portion grasped till it looks straight forwards. The front part of the hoop will, of course, be lower, corresponding in some measure to the slope of the ribs, &c. At the same time the diameters approximate to each other. Con- tinue the turning till the face that looked straight forwards looks upwards and forwards, so that in fact the plane of the grasped portion corresponds to that in which the lower dorsal region of the vertebral column of man lies. The slope of the ribs is lessened, but the interesting points are that the transverse diameter exceeds the antero-posterior, and the exact curve and direction of the surface of the lower ribs are reproduced. Then are seen the twist in the long axis of the rib and likewise that great hollow on each side of the vertebral column which is so marked a feature in the human thorax. I do not overlook the fact that the conditions in the organism are not just the same as they are in this simple hoop ; but I think it will be conceded that where there is a force so constant and so potent in its action as is that of gravitation it will be yielded to by the organism unless there be some good reason to the contrary. Now there does not seem to me to be any such reason here, and it is interesting to observe how closely the thorax of the animal follows the lines of the hoop of steel when the conditions as to gravitation arc the same.