46 



Scientific Proceedings (125) 



that ingested in the milk. The time required to bring about 

 practically complete transformation of the intestinal flora to the 

 acidophilus type varied with the individuals studied, from several 

 days to several weeks. This observation is based on frequent 

 cultural examinations of the stools according to Rettger's tech- 

 nique. In general, the excretion of indican (and of phenols to 

 a less extent), increased early in the treatment with acidophilus, 

 followed by a gradual lowering as the treatment continued; the 

 amounts of these products did not usually fall below those ex- 

 creted before the acidophilus feeding. If indican excretion may 

 be taken as an index of intestinal putrefaction, it appears that 

 implantation of B. acidophilus in the intestine does not neces- 

 sarily lower putrefactive processes in the intestine. 



19 (1979) 



Is cystin synthesized in the animal body? 

 By J. A. MULDOON, G. J. SHIPLE and C. P. SHERWIN 



[From the Chemical Research Laboratory, Fordham University, 



New York City] 



We undertook a series of experiments in order to determine 

 which of the amino acids occurring in proteins were possible of 

 synthesis in the animal organism. According to Abderhalden, 

 any of the aliphatic amino acids should be synthesized, but prob- 

 ably none of the hetero-cyclic or aromatic acids. It has already 

 been shown that glycocoll can be built in the animal organ- 

 ism 1 2 and we have previously shown 3 that glycocoll and also 

 glutamine can be synthesized in the human body at the ex- 

 pense of nitrogen which would otherwise be found in the urea 

 portion of the urine, and peculiarly that both acids are prepared 

 simultaneously as well as singly. 



Recent feeding experiments have shown that cystin is a neces- 

 sary amino acid in protein if growth or maintenance of body 

 weight is desired, therefore indicating that neither cystin nor 

 cystein is synthesized in the organism. 



J McCollum, E. V., and Hoogland, D., Jour. Biol. Chcm., 1913, xvi, 311. 



2 Lewis, H. B., Jour. Biol. Chem., 1914, xviii, 225. 



3 Shiple, G., and Sherwin, C. P., Jour. Amer. Chem. Soc, 1922, xliv, 618. 



