18 



L. A. JULIANELLE 



amino acid figure equivalent to 47 c c of 20/NaOH, and one strain of albus, :i 

 figure of 52 c c of 20/NaOH. They also used the S0rensen method. 



Benton 38 recently observed that in 1.5% peptone broth, staphylococcus shows 

 a decrease in amino acidity until the 5th day, with a following rise until the 

 7th day; in 2% peptone broth, the decrease continues until the 3rd day with a 

 gradual increase until the 9th day; in pure ascitic fluid, after a 1 day decrease, 

 there is a rise until the 4th day. She used the Van Slyke method for amino 

 acid determination. 



In our own experiment, a 2% Difco peptone extract broth was 

 employed. The tubes were inoculated with a 24-hour growth and at the 

 end of each day the amino acidity was determined by the SpYensen 

 method (table 10). 



TABLE 8 

 AMINO ACID DECOMPOSITION OF PEPTONE * 



* In PH column, Pn readings are given. In A. A. column, figures represent number of c c 

 of 20/N NaOH required to neutraliz 100 c c of culture. 



The significant features brought out are that at the end of the first 

 day there is either a slight increase or decrease in amino acid, then a 

 gradual rise to the 4th day, with a falling off on the 5th day. At the 

 time, we assumed that a maximum had been reached on the 4th day. 

 This checks fairly well with the results of Rosenthal and Patai, but 

 brings our maximum a bit sooner than was the case in Benton's work. 



These results differ materially from those obtained with serum 

 broth, but the mediums were of course different. It would seem that 

 in serum broth the amino acids are simultaneously formed and utilized, 



38 Jour. Infect. Dis., 1919, 25, p. 231. 



