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.

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    mentioned high requirement (hygienic albumin minimum in contrast to the phystologic albumin minimum). It appears, however, that proteid metabolism during starvation, even in the same individual, has no constant height, at least not during the first days of fasting. Here it apparently depends upon the composition of the food which has preceded the experiment and on the food products retained in the body. It is high if, in the days preceding the fast, a large amount of albumin has been ingested, and decidedly smaller if for a long time prior to the starvation period the ingestion of albumin has been slight. Only after from one to three days will the nitrogen excretion in the urine, varying in the same individual, show constant figures. This constant figure apparently depends on the composition of the body, i.e., its albumin and fat condition. From this, during starvation, it must make up its losses. The source of the albumin which is so rapidly decomposed during the first days of starvation is not, according to Voit, the albumin of the organs, but the much more easily decomposed and soluble albumin of the fluids, the “ cir- culating albumin.” This quantity, which is increased by a diet rich in albu- min, also determines the proteid metabolism in the first days of starvation. A deficiency of albumin in the food diminishes the amount of “ circulating albumin,” and as this is dependent upon the fixed or organic albumin it indi- rectly works mischief upon the organs. . A superfluous intake of albumin, on the other hand, increases the amount of the readily destroyed circulating albumin in the fluids, and hence propor- tional with the introduction of albumin there is an increased albumin decom- position which is dependent upon the amount of circulating albumin and the N-excretion in the urine. Lhe amount of albumin consumed in a unit of time in the animal body is dependent to an astonishing degree upon the amount of the albumin ingested. The capacity of the normal adult organism to maintain its equilibrium with any amount of albumin—exceeding the minimum—is hardly limited (in so far as the body’s capacity to take up albumin permits investigation). If the energy-requirement of the organism is met by the food, the proteid of food decomposes completely and with extraordinary rapidity. Scarcely absorbed in the fluids, it is soon destroyed, and in the briefest time its nitrogenous cleav- age products appear in the urine for exeretion in quantities corresponding exactly with the increased albumin intake. This fact forms one of the most important points in Voit’s whole theory of nutrition; important both for pathology and for physiology. Hence it became at once the spur for many clinical investigations in metabolism. | Many endeavors have been made to explain these facts. They contradict completely the otherwise applicable law that the amount of decomposition in the animal body is equivalent to its requirement of energy. For Voit has shown that with a sufficient amount of food any additional amount of albu- min, no matter how large, is at once decomposed, so that metabolism (trans- ference of energy) is greatly increased. The changes in the total metabolism by variation of the intake other than those referred to above are slight. The introduction of amounts of