Metabolism Experiment ISTo. 101. 19 



number of mishaps were encountered which prevented a satisfactory deter- 

 mination of oxygen, and while results were obtained for certain periods, they 

 are not considered of sufficient value to publish, and hence they are not here 

 presented. Fortunately, as mentioned above, we have a 3-day experiment with 

 this subject made some 7 months later, in which the oxygen determination was 

 most satisfactory. It is a matter of great regret that during this experiment 

 the determinations of heat were so vitiated by errors in manipulation that no 

 results of value were obtained. 



Material Katabolized in the Body. 



Data for calculation of the total Icatabolism. The amount of food ingested, 

 even when measured for a period of several days or weeks, can not be a true 

 index of the energy requirement of the body as there may be considerable drafts 

 upon the body-material or a storage of body-material during this time without 

 any especial gain or loss in body-weight. If each gram of fat or glycogen 

 withdrawn from his store in the body was expressed by a loss in body-weight 

 of 1 gram this method of estimating the energy requirement would obviously 

 hold true, but the proportion of water in the body at different times may vary 

 to a marked degree, and especially is this so when there are noticeable changes 

 in dietetic habits. It has been clearly shown that the ingestion of a carbo- 

 hydrate-rich diet results in a storage of water in the body, while a carbohydrate- 

 poor diet results in a noticeable loss of water. In an experiment reported by 

 Benedict and Milner l the actual weight of total food consumed with a carbo- 

 hydrate-rich diet covering a period of 3 days was actually much less than the 

 total weight of food consumed in a subsequent 3-day period with a carbo- 

 hydrate-poor diet containing the same amount of energy. During the latter 

 experiment with a high-fat diet however there was a marked loss in body- 

 weight. Consequently, in studying the dietetic requirements of different indi- 

 viduals, particularly the energy requirements, it is absolutely necessary either 

 to continue the experiment for periods covering several months with accurate 

 weighings of both income and outgo and to determine simultaneously variations 

 in body-weight, or to make a complete metabolism experiment in which the 

 total gaseous exchange is determined for periods of not less than 24 hours. 



There had previously been many experiments on the metabolism of this 

 subject which seemed to indicate, so far as the deductions of some of the 

 investigators are concerned, that he could subsist on a diet containing a much 

 smaller amount of total energy than the average man consumed in his cus- 

 tomary diet. It was therefore of particular interest to us to make the study 

 with this subject, although it was a matter of great regret that the oxygen and 

 heat determinations were unsatisfactory. We were able, however, to obtain the 

 excretion of carbon in the respiration, and nitrogen in the urine, and these, with 

 the data of his later experiment, suffice to give us a reasonably accurate picture 

 of his katabolism. 



1 Benedict and Milner, U. S. Dept. Agr., Office Exp. Stas. Bui. 175, p. 225, 1907. 



