222 Proceedings Columbia Biochemical Association [March, 



seven-day fast.^^ F. D. Zeman and Paul E. Howe. The 

 third^^ of a series of experiments on changes in metabolism of man 

 following the Ingestion of food after a fast. In the recuperation 

 periods (4 days) of this experiment, non-protein and normal diets 

 were fed; the preliminary and final diets were the same. The non- 

 protein diet consisted of sucrose, clarified butter, alkalin salt mixture, 

 and agar-agar, having an approximate daily fuel value of 3500 cal. 

 Determinations were made of the body weight, and the excretion of 

 urinary water, total nitrogen, urea, ammonia, creatin and Creatinin.^* 



The excretion of the urinary constituents followed the usual 

 course during the fast; the total-nitrogen excretion on the 7th day 

 was approximately 10 gm. and creatin appeared daily. The inges- 

 tion of a calorically sufficient, non-protein, diet resulted in decrease 

 of the nitrogen excretion, which became constant on the ßd and 4th 

 days. Minimum values obtained on the 2nd day of feeding, were as 

 follows: Total N, 3.56 gm.; urea-N, 1.59 gm.; ammonia-N, 0.54 

 gm.; creatinin-N, 0.61 gm.; creatin-N, 0.05 gm. A relatively high 

 ammonia-N excretion (0.72 gm., 17.4 percent of the total N) oc- 

 curred on the 3d day. Normal conditions tended to return in the 

 final period while the subject was retaining nitrogen. Lowered ab- 

 solute and relative ammonia-N excretions were observed. The daily 

 excretion of fecal nitrogen during the non-protein period was 

 0.50 gm. 



A comparison of the changes in body weight, and in the nitrogen 

 balances, shows an increase in body weight during the non-protein 

 feeding period, accompanied by a loss of nitrogen; the reverse oc- 

 curred in the final period. The initial increase in weight after the 

 ingestion of food was the result, chiefly, of the retention of water 

 and to a smaller degree of non-nitrogenous food substances. 



170. Variations in factors associated with acidity of human 

 urine, during a seven-day fast and during subsequent non-pro- 



22 Most of the work was done in the Biochemical Laboratory at Teachers 

 College. 



23 The first two experiments were reported by Howe, Mattill and Hawk: 

 Jour. Amer. Chem. Soc, 191 1, xxxiii, p. 568, and Howe and Hawk: Proc. Amer. 

 Soc. Biol. Chem., 1912, ii, p. 65 ; Jour. Biol. Chem., 1912, xi, p. xxxi. 



2* Variations in factors associated with changes in the urinary acidity are 

 referred to in the succeeding abstract. 



