A treatise on the blood, inflammation, and gun-shot wounds / by John Hunter ; with notes by James F. Palmer.

  • John Hunter
Date:
1840
Catalogue details

Licence: Public Domain Mark

Credit: A treatise on the blood, inflammation, and gun-shot wounds / by John Hunter ; with notes by James F. Palmer. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

    97/618
    Another observation occurs, viz., that the whole of the limb below the ligature, where the crural artery had been taken up, must have been entirely supplied with such altered blood ; and as it kept its life, its warmth, and the action of its muscles, it is evident that the colour of the blood is of little service to any of those properties. It is pro- bably from this cause that granulations on the lower part of the lower extremity look dark when the person stands erect, as well as in very indolent sores, however situated. Another observation strongly in favour of the supposition that rest is a cause of the change of blood from the scarlet colour to the dark or modena, is taken from the common operation of bleeding; for we generally find the blood of a dark colour at its first coming out, but it becomes lighter and lighter towards the last. Some reasons may be given for this: first, it has stagnated in the veins while the vein was filling, and the orifice making, which occupy some lime, and may render it darker than it otherwise might have been in the same vein; secondly, when there is a free orifice the blood may pass more readily into the veins from the arteries, and therefore may be somewhat in the state of arterial blood, which may occasion the last blood to be rather lighter. What amounts almost to a proof of this is, that although a ligature is tied so as to stop the passage of the blood to the heart, and therefore it might be supposed not to have so free a passage from the arteries as in com- iii)ii, yet, from the following observations, it appears that it cer- tainly has a much freer; for if the orifice be large in a full-sized vein, the arm beyond the orifice will be much paler than the natural colour, and the blood will become more florid; but if, on the con- trary, the vein be small, and little blood passes, it will retain its dark colour; this, however, would appear not always to be the case. I bled a lady, whose blood at first was of a dark colour; but she fainted, and while she continued in the fit the colour of the blood that came from the vein was a fine scarlet. The circulation was then very languid. We may observe that venal blood in the most healthy is com- monly, if not always, the darkest; and that whenever the body is the least out of order, it is then not so much changed from the florid to the very dark purple. This I have often observed, and particu- larly recollect a striking instance of it in a gentleman who had a florid throughout the whole system of those animals which perished from cold {Dr. 1Jodgkin's Notes to Edwards*) ; whereas, under the influence of moderate warmth, such as that of the body, these changes take place, slowly on extravasated or stagnating' blood, but instantly in the extreme capillaries. It will be sufficient to have noticed in this place the analogy which subsists be- tween the venalization of the blood under these different circumstances, without pretending to decide whether these phenomena depend on the gradual union of carbon and oxygen with each other, or on any other cause.. The subject will be resumed in a future note.] » Se^ I'll wards on Physical Agents, &c, published in the Select Medical Library for 1838. 9