Blood : a study in general physiology / by Lawrence J. Henderson.

  • Lawrence Joseph Henderson
Date:
1928
Catalogue details

Licence: In copyright

Credit: Blood : a study in general physiology / by Lawrence J. Henderson. Source: Wellcome Collection.

    99/434 page 73
    This is always true of normal human blood, because there is always more than enough protein to take up all the base bound by carbonic acid. For separated serum, how¬ ever, this is not the case. In sum, the carbon dioxide dis¬ sociation curve of blood expresses the net result of all the processes which have just been analyzed. Oxygen is absorbed by blood in small amounts as free dissolved oxygen and otherwise exclusively as the com¬ pound oxyhemoglobin, formed by chemical reaction be¬ tween hemoglobin and oxygen. This reaction has been the subject of many investigations, but is not yet well under¬ stood either chemically or physico-chemically. For a pure dilute solution of hemoglobin the oxygen dissociation curve was formerly believed to bear some resemblance to a curve defined by the equation, 1c- [Hb] [Hb02] p°2’ which expresses the condition for equilibrium in the chemical reaction, Hb02 ^ Hb -f- 02. However, it is difficult to find hemoglobin solutions which fit this condition over a wide range of oxygen pressure, and experimental work with pure hemoglobin is very troublesome on account of the formation of methemoglo- bin and for other reasons. Also the shape of the curve is greatly modified, as Barcroft’s numerous experiments have shown,61 when the concentrations of electrolytes in the solution are varied. Finally, as we have already seen, there is evidence that the true reaction between oxygen and hemoglobin is Hb408 = Hb4 + 402, corresponding to a molecular weight of 67,000 for hemo- 61 J. Barcroft, The Respiratory Function of the Blood, 1st ed., chap. IV, Cambridge, England, 1914.
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