1915I Edgar G. Miller, Jr. 223 



tein and normal feeding periods.^^ F. D. Zeman, Jerome Kohn 

 and Paul E. Howe, A study was made of the variations in acidity 

 (true and titratable) of human urine, with relation to modifying 

 factors present during fasting and recuperätion. The ränge of var- 

 iations of the acidity extended from a fairly acid urine, Ph 5-I (3^^ 

 day of fast) to an alkalin urine, P3 8.0 (last day of the final period). 

 The diet of the preliminary and final feeding periods was the same, 

 in nature, as that used in previous experiments.^^ In the non-pro- 

 tein period, sucrose, clarified butter, salts (alkalin mixture) and 

 agar-agar were ingested. Determinations were made of the H^ ion 

 conc. (indicators) : titratable acidity or alkalinity (with Phenolphtha- 

 lein, neutral red and methyl orange); phosphates; ammonia; ace- 

 tone-aceto-acetic acid ; and /3-hydroxy butyric acid. 



In the absence of exogenous phosphorus (fasting) we found the 

 acidity (true and titratable), phosphates, acetone-aceto-acetic acid 

 and total nitrogen, varied together. During the non-protein, post- 

 fasting, period there was an increased H^ ion conc. and acidity, with- 

 out accompanying increase in nitrogen excretion ; acetone and aceto- 

 acetic acid were absent. The increased excretion of ammonia in 

 fasting is correlated with that of i8-hydroxy butyric acid ; when not 

 influenced by this factor, as in the preliminary, non-protein, and 

 final feeding periods, the ammonia excretion fluctuated with the H"*" 

 ion conc. and the acidity. The low ammonia excretion in the final 

 period showed that the low H"^ ion conc. and titratable acidity re- 

 sulted from a loss of fixed base. This phenomenon is apparently 

 characteristic of recuperätion (nitrogen retention). 



It seems probable that increased nitrogen excretion during the 

 early days of a fast in a human individual is related to metabolic 

 processes that result in the excretion of aceto-acetic acid. 



III. TWENTIETH MEETING 



The twentieth scientific meeting of the Assoc. was held in the 

 Biochemical Seminar Room, at the Columbia Med. Seh., at 4:^5 



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

 College. 



26 Howe, Mattill and Hawk: Jour. Anier. Chem. Soc, igii, xxxiii, p. 568. 

 Howe and Hawk: Proc. Amer. Soc. Biol. Chem., 1912, xii, p. 65; Jour. Biol. 

 Chem., 1912, xi, p. xxxi. 



