Diseases of metabolism and of the blood : animal parasites, toxicology / edited by Richard C. Cabot.

Date:
1906
Catalogue details

Licence: Public Domain Mark

Credit: Diseases of metabolism and of the blood : animal parasites, toxicology / edited by Richard C. Cabot. Source: Wellcome Collection.

    27/684 (page 7)
    3852 grams of carbohydrate, containing 19.5 grams of N and 315.5 grams of C, besides 2,016 grams of water. He excreted in complete rest: er GBS MIG i sca ok oe ee eo dee 17.4 grams N., 12.7 grams C., 1,279 grams water. ee acc an laud 2a wa twee's oo re ea i | SS Ge Ss © ‘water. Bit LNG POSPIPALION:.. unse ee 2480... 76, 828 “ water. eek 190. 2° UN, 208 720... 23190 *- water, The body was, therefore, in N-equilibrium ; excreted 174 grams of water and retained 39.8 grams of carbon, which corresponds to a deposition of 52 grams of fat. | This method gives us knowledge of the body-albumin during the investiga- tion. This is estimated by means of the nitrogen balance, a method which, since that time, has come into general use. One hundred grams of albumin contain 16 grams of N. If the entire amount of N due to the decomposition of albumin during the trial period were excreted in the urine, the N figure of the urine need only be multiplied by 6.25 to determine the amount of albumin metabolism. The other N losses of the body are shght. A small portion appears in the feces as a residue of the intestinal secretions and this is sufficiently large to be calculated in each investigation. The other N losses of the body (loss of hair, scales of the epidermis and sweat) are so insignificant that they may be ignored in a trial | period lasting twenty-four hours. Nitrogen equilibrium is then shown when the food-N = urinary-N + fecal-N. Voit’s quantitative method of estimating metabolism also permits us to recognize from the carbon balance whether the body’s need of N-free sub- ‘stance has been fulfilled by the food given during the trial period or not. The organism has its very definite calory requirement. With an insufficient administration of nourishment, the body takes a supply of energy from its own material component parts. When, in a body previously in equilibrium, carbon is retained or more excreted than is ingested, a corresponding accumu- lation or loss of fat is indicated. In the form of carbohydrates (glycogen) the body does not accumulate any great supply of energy. In the quantitative estimation of metabolism in the clinic it has been necessary as a rule to proeeed without determining the carbon balance. This require: the estimation of the total CO, excretion in the respired air, which ean only be accomplished by means of a large respiratory apparatus such as that of Pettenkofer. Such an apparatus is expensive and very difficult to adjust. As many hours are required to make the experiment, it is incon- venient to employ this apparatus at the bedside. To compensate for this, the condition of the body-weight has been em- ployed as a control to determine whether, besides the proteid requirement, a sufficient energy supply for the needs of the organism is present in the food. If there is little variation in the material constituents of the body (albumin, fat and water), this is permissible, especially if the experimental period is not too brief. Instead of trials of twenty-four hours, therefore, trial periods of three to four days are usual in metabolism analyses of this type.