286 



FOOD INGESTION AND ENERGY TRANSFORMATIONS. 



greater than that noted either with carbohydrate food materials or 

 with fats. This effect in practically all instances continues over a 

 much longer tune than with either of the other nutrients, thus putting 

 this protein food material in a distinctly special class so far as the 

 influence upon the metabolism is concerned. 



PROLONGED EFFECT OF PROTEIN. 



Two respiration experiments were carried out in July, 1911, to study 

 the metabolism several hours after the ingestion of beefsteak. In both 

 instances the steak was eaten at midnight and the subsequent experi- 

 ments began at approximately 8 h 30 m a. m. 



In the experiment with H. F. T., July 14, 1911, the subject ate 206 

 grams of beefsteak, with a nitrogen content of 9.46 grams; the first 

 observation was made at 8 h 36 m a. m. The heat production for this 

 period, as shown by table 217, was 0.92 calorie per minute. The two 

 succeeding periods did not show materially different results. If we 

 compare the heat production in this experiment with the basal value 

 of 0.92 calorie per minute found for this subject on July 10, 1911, 

 it is clear that the effect of 206 grams of beefsteak had entirely passed 

 at the end of 8| hours. The nitrogen excretion for approximately 11 

 hours after the ingestion of the food was as follows: Between Il h 45 m p. m., 

 July 13, and 7 a. m., July 14, 0.80 gram per hour; between 7 a. m. and 

 10 h 40 m a. m., July 14, 0.69 gram per hour. 



TABLE 217. H. F. T., July 14, 1911. Lying. (Values per minute.) 



Beefsteak: 



Amount, 206 grams; nitrogen, 9.46 grams; total energy, 428 cals. 

 Fuel value: 346 cals.; from protein, 70 p. ct. ; from fat, 30 p. ct. 





beefsteak eaten at 12 midnight July 13. 



A similar experiment was made with the subject H. L. H., on July 

 15, 1911, in which 249 grams of beefsteak, with a nitrogen content of 

 11.44 grams, were eaten at midnight; beginning at 8 h 59 m a. m. the 

 next day, the metabolism was observed approximately every hour, 

 the last observation being at 3 h 16 m p. m. The results of the experi- 

 ment are given in table 218. The calories per minute varied from 

 1.15 to 1.31, the highest value being found in the last period. Com- 

 paring these results with the basal heat production of 1.11 calories 



