396 



SCIENCE 



[N. S. Vol. XXXVII. No. 950 



the most heated. These discussions will be 

 necessarily brief. 



SODIUM BENZOATE 



On certain phases of the behavior of 

 sodium benzoate there is an abundant lit- 

 erature. Following the pioneer investiga- 

 tions of Meissner and Shepard, and Bunge 

 and Schmiedeberg on the synthesis and 

 estimation of hippuric acid it was recog- 

 nized that benzoic acid, cinnamic acid, 

 quinic acid and other bodies are normally 

 combined in the animal organism with 

 glycine and excreted as hippuric acid. It 

 was shown, also, that many aromatic fruits 

 and vegetables contain these organic acids 

 which go into the benzoyl combination. 

 Numerous later studies have shown the ex- 

 tent of the glycine, or potential glycine, 

 available in the human body for combina- 

 tion. 



With the recognition of this normal 

 character of the hippuric acid synthesis no 

 great objection was raised to the adminis- 

 tration of large doses of the benzoate in 

 certain diseases, and going back some 

 thirty years we find a considerable record 

 of clinical experience on the dosage of ben- 

 zoates in pulmonary tuberculosis, rheuma- 

 tism and diphtheria. It was shown by 

 many physicians that doses of 5 to 25 

 grams a day might be given without ap- 

 parent harm to the patient. This extended 

 experience was sufBcient to show that the 

 toxic effect of the benzoate was of a very 

 low order, not much greater possibly than 

 that of sodium chloride. 



At the time when sodium benzoate was 

 considered important therapeutically the 

 question of its use as a food preservative 

 had not arisen, and the interest attaching 

 to it then and through the following dis- 

 cussions was in no wise influenced by the 

 present practical question. To what ex- 

 tent may benzoic acid be combined or de- 



toxified in the animal organism! The 

 earlier observers soon recognized that or- 

 dinarily and normally it combines with 

 glycine to form hippuric acid, and the 

 question of the available supply of this 

 amino acid was discussed for a long time. 

 In 1898, in experiments on rabbits, Wiener^ 

 concluded that while large doses of benzoic 

 acid, about 1.7 gram per kilogram of body 

 weight, were usually fatal, smaller amounts 

 and up to the quantity yielding 1 gram of 

 hippuric acid per kilogram of body weight, 

 were combined and detoxified. He believed 

 that the value for the combined benzoic 

 acid, that is, the hippuric acid, was rather 

 constant, the maximum being the 1 gram 

 per kilogram of weight. The usual figures 

 were between 0.7821 and 0.8345 gram per 

 kilogram. From this he concluded that 

 the available supply, or stored-up glycine, 

 must amount to 0.3276 to 0.3496 gram per 

 kilogram of weight. He observed that free 

 benzoic acid appeared in the urine when 

 amounts in excess of the maximum values 

 quoted were ingested. 



These observations were made at a time 

 when glycine was looked upon as an im- 

 portant intermediary product of protein 

 metabolism, and before much was known 

 concerning the quantitative relations of 

 the amino acids in the protein molecule. 

 It was later shown that the mean glycine 

 content of the ingested proteins is not far 

 from 4 per cent, of their weight, and that 

 the benzoic acid combined to form hip- 

 puric acid may be far greater than the 

 weight corresponding to this glycine con- 

 tent. A stored-up reserve of glycine was 

 for a time assumed to account for the re- 

 markable hippuric acid formation reported 

 by several observers, but this view has been 

 pretty generally abandoned. In this con- 

 nection the researches of Parker and Lusk,^ 



' Schmied. Arch., 40: 313. 



'Am. Jmir. Phys., 3: 472. 



