Inquiry into the causes of the motion of the blood : with an appendix, in which the process of respiration and its connexion with the circulation of the blood are attempted to be elucidated / by James Carson, M.D.

  • Carson, James, 1772-1843.
Date:
1815
Catalogue details

Licence: Public Domain Mark

Credit: Inquiry into the causes of the motion of the blood : with an appendix, in which the process of respiration and its connexion with the circulation of the blood are attempted to be elucidated / by James Carson, M.D. Source: Wellcome Collection.

Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

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    the united capacities of the extreme capillaries. The bore of the trunk of the aorta compared with that of the branches united into which it has ultimately divided, lias been attempted to be de- termined, but the conclusions to which fhese at- tempts have led, have been often widely different. According to Keil, the bore of the aorta is to that of the extreme vessels united as 1 to 44,-500.— According to Helvetius and Sylva, as 1 to 700: as490,000 to 1113,490, according; to the calcula- tion* of Senac. Martin maintains that the diameter of a trunk or stem is equal to the cube root of the diameters of its immediate branches united. Calculators have not been able to arrive at any certain conclusions on this subject. Some im- perfect notion may be formed of the difference of the capacity of the aorta and that of its ultimate ramifications united, by considering the different velocities of the blood ill the aorta and in the ex- treme vessels ; as the square of the diameter of the aorta will be to that of the diameter of all the last ramifications in the inverse ratio of the velo- cities of the blood at these parts. From the obser- vations that have been made respecting the motion of the blood in the extreme vessels of transparent parts, it is evident that the capacity of all the ultimate branches must in a vast degree exceed that of the arterial trunk.