The Synthesis of Benzoyltaurin. 405 



cholic acid although in the bile of the dog and of the sheep tauro- 

 cholic acid appears to be the only bile salt present. 1 



No adequate theory has been advanced to explain the specific 

 r61e which is thus played by these amino acids. It cannot be 

 entirely a question of availability since probably all of the amino 

 acids appear in the blood stream. The facts at hand are still too 

 few to warrant an hypothesis. An attempt was made a number 

 of years ago by Koelker and Amberg 2 to influence the normal 

 course of the synthesis of hippuric acid. On simultaneous admin- 

 istration of benzoic acid and dl-leucin, benzoyl leucin did not 

 appear in the urines of the experimental rabbits while the presence 

 of hippuric acid and free benzoic acid was easily shown. The 

 authors conclude that dl-leucin possesses a detoxifying effect on 

 the action of benzoic acid although no explanation is offered as to 

 the mechanism of this action. 



Animal Experiments. 



It appeared to us that since taurin behaves in nearly all re- 

 spects like an amino carboxylic acid 3 and that since both taurin 

 and glycocoll are combined with cholic acid as bile salts, an oppor- 

 tunity was afforded for the possible substitution of taurin for gly- 

 cocoll when benzoic acid is ingested. Taurin, when administered 

 to the dog or to man, is not broken down but is excreted in the 

 urine unchanged. 4 An opportunity is thus afforded not only for 

 the possible conjugation with benzoic acid in the body but also 

 for the estimation of uncombined taurin in the urine. Benzoic 

 acid and taurin were simultaneously fed to both man and to dogs. 

 The dose of the latter substance was several times that required 

 to combine with the amount of benzoic acid which was given. 

 In the experiments of the first series estimations of total nitrogen, 

 amino nitrogen, free and conjugated benzoic acid (Folin and 

 Flanders), 5 neutral sulfur, total sulfates and total sulfur were 



1 Schmidt, C. L. A., and Dart, A. E., J. Biol. Chem., 1921, xlv, 415. 



3 Koelker, A. H., and Amberg, S., J. Pharmacol., 1910-1911, ii, 59. 

 'Schmidt, C. L. A., Proc. Soc. Exp. Biol, and Med., 1921, xviii, 204. 



4 Schmidt, C. L. A., Von Adelung, E. and Watson, T., J. Biol. Chem., igiS > 

 xxxiii, 501. Schmidt, C. L. A. and Allen, E. G., J. Biol. Chem., 1920, xlii, 55. 



5 Folin, O., and Flanders, F. F., J. Biol. Chem., 1912, xi, 257. 



