CONSUMPTION OF FOOD IN THE HEALTHY 11 



mentioned high requirement (hygienic albumin minimum in contrast to the 

 physiologic 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 alhumin." 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. 



The amount of albumin consumed in a unit of time in the animal iody 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 excretion in quantities corresponding 

 exactly with the increased albumin intake. This fact forms one of the most 

 important points in Volt'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 



