An introduction to medical literature, including a system of practical nosology : intended as a guide to students, and an assistant to practitioners. Together with detached essays, on the study of physic, on classification, on chemical affinities, on animal chemistry, on the blood, on the medical effects of climates, on the circulation, and on palpitation / by Thomas Young.

Date:: 1823

Credit: An introduction to medical literature, including a system of practical nosology : intended as a guide to students, and an assistant to practitioners. Together with detached essays, on the study of physic, on classification, on chemical affinities, on animal chemistry, on the blood, on the medical effects of climates, on the circulation, and on palpitation / by Thomas Young. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

563/700 page 529

by considerations which are perfectly unanswerable, that the crystalline lens possesses an internal power of altering its form, analogous to that of other muscular parts ; and the crystalline lens contains no fibrin.] 3. Respiration. Cigna, Scheele, Lavoisier, Menzies, Goodwyn, Beddoes, Davy, Henderson and Pfaff have made many experiments on respiration. Dalton’s doctrine, of the expulsion of one gas from an aqueous fluid by another, ex- plains some of the apparent irregularities, respecting the accidental absorption of nitrogen. But Allen and Pepys, who have continued these investigations with great accuracy, have found more nitrogen evolved from a Guinea pig, than could possibly be contained in all its fluids. It has been commonly supposed, that the whole mass of the blood operates on the air, absorbing its oxygen, and giving out carbonic acid : but this opinion is incorrect: the whole of the blood rapidly absorbs oxygen when shaken with it, and takes up, at the same time, a good deal of the carbonic acid that is formed : but serum, freed from the coloured particles, does not materially change the air until it begins to putrefy. The greatest part of the effects of the blood on the air belongs therefore to the colouring particles; and as this portion of the blood does not penetrate the capil- lary vessels in general, except in a very few of the secreting organs, and is therefore not employed in the growth or repair of the body, it seems very probable that it is principally con- cerned in the preservation of temperature. This process may be explained according to the ingenious and important theories and researches of Dr. Crawford ; and it appears, from the experiments of Allen and Pepys, that as much heat must be evolved in 24 hours, as results from the combustion of about a pound of coal, or even more, since it is possible that still more heat may be evolved by the carbon, which is in a liquid state previously to its combination with oxygen, than by solid carbon. [But what becomes of all this heat, when the man is living in a temperature of 100° ?] It must, 2 M

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