Text-book of physiological and pathological chemistry : in twenty-one lectures : for physicians and students / by G. Bunge ; translated from the second German edition by ... L.C. Wooldridge.

  • Bunge, Gustav von, 1844-1920.
Date:
1890
Catalogue details

Licence: Public Domain Mark

Credit: Text-book of physiological and pathological chemistry : in twenty-one lectures : for physicians and students / by G. Bunge ; translated from the second German edition by ... L.C. Wooldridge. 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.

    89/494 (page 71)
    sition and oxidation of the body, as an organic compound, in union with a part of the carbon and hydrogen, and, in the case of man, principally as urea. The amount of urea which can be formed from the albumen, is about one-third of the weight of the albumen. In order, therefore, to ascertain the heat-equivalent of the proteid in our organism, we must deduct one-third of the heat-equivalent of urea from that of the albumen. But this figure would come out rather too high, because the nitrogen leaves our body not only as urea, but partly as a compound containing both more carbon and more hydrogen. We must therefore subtract at least 800 units of heat from the heat-equivalent of the proteids in the above table, and we then obtain figures which are only a little higher than those of the carbohydrates. As a store of energy in our bodies, therefore, the carbohydrates are, in a ' quantitative respect, about equivalent to the proteids. The heat-equivalent of fats, on the other hand, is twice as great. Little has as yet been ascertained as to the manner in which the organs, in the performance of their various func- tions, utilize the potential energy acquired by the storage of food. As muscle is made up chiefly of albuminous matter, it was a plausible supposition that proteid was the source of muscular work. This view was maintained by Liebig, who contrasted the foods containing no nitrogen—the fats and carbohydrates—as respiratory foods with the proteids as plastic foods. He taught that the former served mainly to generate heat. At the present time we know that, in the work of muscle, the excretion of nitrogen is increased only in a sHght degree, but that the excretion of carbonic acid and the absorption of oxygen is notably increased; that therefore muscle works principally with material free from nitrogen. We know that a store of carbohydrates is to be found in the muscles in the form of glycogen, and that this store disap- pears during work. It thus appears that the carbohydrates