The respiratory function of the blood.

  • Barcroft, Joseph, 1872-1947.
Date:
1914
Catalogue details

Licence: In copyright

Credit: The respiratory function of the blood. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    Till recently there have been two schools of thought with regard to the meaning of the figures given. Of these the first teaches that the sources of analytical error are so great as to make more accurate analysis impossible, whilst the second, represented chiefly by the late Professor Bohr of Copenhagen, frankly admits that the want of uni- formity is so great as to render untenable the idea of haemoglobin as a simple substance. He explains the divergencies which we have noted as being due to a mixture in different proportions of four substances which he calls a, y8, 7 and S haemoglobins'^', each with a different oxygen capacity from the others. To the two schools mentioned above has now been added a third which teaches that the combination of oxygen and haemoglobin is not in the old-fashioned sense a chemical combination at all, but that it is a manifestation of the physical phenomenon known as adsorption, and that it therefore depends essentially on the surface conditions of the molecules of oxygen and haemoglobin respectively. The pro- perties of these surfaces may presumably be altered by all sorts of variations in the collateral substances which are present in the solution of the uniting molecules. The amount and nature of the salts present for instance might be supposed to alter the charges on the molecules, and in so doing to affect the amount of oxygen with which a given quantity of haemoglobin would unite. Within recent years, partly on account of the improvements in the analytical methods both for oxygen and iron and partly on account of the increased importance of the subject, it has become more and more desirable that some re-investigation by direct methods of this specific oxygen capacity of haemoglobin should take place. I mean by methods in which the oxygen is measured as such, and the iron as a salt of the metal, as opposed to the indirect spectro-photo- metric methods which have given uniform, and apparently excellent results in the hands of Butterfield This investigation has lately been undertaken by Peters; for the purpose of estimating the oxygen he has used the differential method of blood analysis based upon the observation of Haldane'«> that oxygen is eliminated from haemoglobni quantitatively by potassium ferricyanide. The theoretical accuracy ot the method has been confirmed by the researches of Professor Franz Muller <i°' in Berlin, while its practical details have been so far simpli- fied that some half-dozen analyses can easily be performed with ^is many cubic centimetres of blood in two hours. Peters therefore has been at a great advantage as compared with his predecessors, whose