Dr. John Mayow : the Harveian oration for 1899 / by A. Crum Brown.

  • Brown, Alexander Crum, 1838-1922.
Date:
1899
Catalogue details

Licence: Public Domain Mark

Credit: Dr. John Mayow : the Harveian oration for 1899 / by A. Crum Brown. Source: Wellcome Collection.

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

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    lungs, the exhalations caused by the commotion of the blood are also blown out.” Mayow now inquires what it is in the air that is taken up by the blood in the lungs, and concludes that it is the same nitro- aerial spirit that causes lire by acting on the sulphureous (i.e. com- bustible particles). It acts in the blood also on the sulphureous (combustible) matter there, not only in the lungs and heart, but all through the arteries, and so produces the animal heat. In a chapter of the tract, “ De Sal nitro et spiritu nitro aerio,” which is devoted to the Bath waters (you will remember that he practised medicine in Bath), we find a remarkable passage. He has found that water (not Bath water only) contains air which can be expelled from it by heat, and he goes on to say, “ To this I add, lastly, that the air interspersed in the particles of water is inhaled by fish for respiratory purposes. And, indeed, the gills with which fishes are endowed seem contrived for this end, that the air (which is absolutely necessary for animal life) may be separated by their action from the water, and most intimately mixed with the mass of the blood. And hence it is that fishes are always alternately drawing in and letting out water, just as terrestrial animals do common air, because a vital aerial something separated by them from the water, as by the others from the air, is sent into the mass of the blood.” With Mayow the answer to one question always leads to the asking of another. So here, having shown that the main use of respiration is to bring the vital aerial spirit into the blood, he goes on to ask what good does it do there ? He has shown that it produces animal heat, but that is not enough ; he goes on to show that respiration and the absorption of nitro- aerial spirit are necessary for motion. He says: “We may then suppose that nitroaerial particles derived from the inspired air constitute the one set of motive particles, the other being the saline sulphureous particles supplied by the mass of the blood; these meeting in the motor parts produce that effervescence from which muscular contraction proceeds. . . . Nor indeed is motion produced in the heart in any other way from that in which it is produced in other muscles, for I do not think that the effervescence which causes the motion of the heart (for reasons given above) takes place in the ventricles, but in the muscular substance of the heart, just as in other muscles. Wherefore, on the cessation of respiration, when that aerial salt necessary for any movement fails, the pulsation of the heart, and consequently the flow of blood to the brain, are interrupted, and death necessarily follows And this further use of respiration can be confirmed. For in active exercise and violent movements there is surely need of more intense and more frequent respiration, not so much that a greater flow of blood may freely pass through the lungs, for we have shown that this can take place without respira- tion, but because there is a very great expenditure of the nitro-