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.

    35/610 (page 13)
    likely to kill it if alive; as every change likely to impair life pro- motes coagulation, for example, debility, fainting; and as blood frozen, and therefore likely to be killed if alive, and again thawed, instantly coagulates. But the coagulation appears, in most in- stances, if Dr. Scudamore's experiments be accurate, though others have not found the same resultsb, attributable merely to the escape of carbonic acid: and as coagulated blood or fibrine (and the coagulated part of effused blood is fibrine) becomes vascular, one can hardly, if the fluid is alive, regard a coagulum as ne- cessarily dead. See also Sect. VI. Note B. Large quantities of blood are found fluid in every dead body, showing that simple loss of vitality is not sufficient to cause coa- gulation. Indeed, the blood of the heart and vessels is found, most frequently, in opposite states, fluid in one part, coagulated in another, yet it is all equally dead. From all these contradic- tory circumstances, I regard the coagulation of the blood as quite unconnected with its vitality or lifelessness, and as entirely a che- mical result. That it, however, is influenced by the vital pro- perties of the containing vessels is possible, but these may ope- rate upon the blood, in this respect, as a mere chemical compound; and even if it be alive, and they influence its life, still the in- fluence, as far as respects coagulation, may in effect be chemical. The blood generally coagulates in the living body on escaping from its vessels, and even in its vessels if its motion be prevented by ligatures ; and when it does not, its subsequent escape from the body almost always produces instant coagulation.0 It almost always coagulates also in the vessels running through healthy parts to others in a state of mortification, and in large vessels adjoining a pulmonary abscess; in which cases, the final cause — prevention of haemorrhage, is evident. The efficient cause, however, in all these examples is unknown. In all, the blood is still in contact with living parts : in the two last, it is not at rest till it coagulates. J. Hunter, after mentioning that after a mortification of the foot and leg he found the crural and iliac arteries completely filled with strongly coagulated blood, adds, that this could not have arisen from rest, because the same thing ought then to hap- pen in amputation, or in any case where the larger vessels are tied up.d Besides, coagulation after extravasation, or when a b Dr. Turner, Elements of Chemistry, 1827. p. 638. c J. Hunter mentions the coagulation of blood let out from the tunica va- ginalis, in which it had lain fluid sixty-five days after a wound. On the Blood, ]». 2.5. d 1 c. p. 23.