The elements of physiology / by J. Fred Blumenbach.

  • Johann Friedrich Blumenbach
Date:
1828
Catalogue details

Licence: Public Domain Mark

Credit: The elements of physiology / by J. Fred Blumenbach. 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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    solids originally, and ever afterwards their nourishment; and from which all the other fluids, with the exception of the crude (4), are secreted and derived. Of the multifarious im- portance of the blood, we shall speak particularly hereafter. NOTES. (A) Most cold-blooded animals, as fishes and the amphibia, have a much smaller proportion of blood and fewer blood-vessels than those with warm blood, though a much greater number of colourless vessels arising from the arteries. In. an experiment which Blumenbach made on this subject, he obtained from twenty-four adult water-newts (lacerta palustris), which had been just caught,and weighed each an ounce and a half, 3hiss, of blood. The proportion to the weight of the body was as 2§ to 36, while in healthy adult men it is as 1 to 5.° (B) Dr. Magendie stated, in 1809, to the Institute, that this as- sertion is incorrect. If air is injected rapidly, the animal screams and dies in a moment: but if slowly, he informs us that no incon- venience results, and that some animals bear the injection of enormous quantities without perishing.p Dr. Blundel injected five drams into the femoral vein of a very small dog, with only temporary inconvenience, and subsequently three drams of ex- pired air even without much temporary disturbance.0! Nysten has established, that many gases soluble in the blood, as oxygen and carbonic acid, may be thrown into the circulating system in very large quantity without serious inconvenience; while danger often ensues upon the introduction of those which are sparingly or not at all soluble in the blood.1' In the same way, if about 15 grains of bile are rapidly introduced into the crural vein of an animal, instant death occurs; but, if slowly, no inconvenience results. This quantity may be even rapidly injected into the vena portae without injury, and so likewise may atmospheric air, probably because the extreme subdivision of the vessel acts like .slowness of introduction, — causes the com- plete diffusion and dilution of the bile, and solution of the air, before it reaches the heart. 0 Comparative Anatomy, ch. xii. ed. ]. p. 245. Translated by Mr. Lawrence. p Precis EUmentaire de Physiologic 2d edition, 1825. t. ii. p. 433. sqq. Med, Chir, Trans. 1S18. p, 65. sq. r Magendie, I. c.