March 14, 1913] 



SCIENCE 



397 



Wiechowski,* Cohn/ Magnus-Levy," Lew- 

 inski' and others, should be referred to. 

 All of these observers found that in the 

 increased ingestion of large amounts of 

 benzoic acid in animals there was an in- 

 creased protein metabolism, with increas- 

 ing amounts of the benzoic acid not com- 

 bined as hippuric acid. In the Lewinski 

 investigations rather large weights of ben- 

 zoic acid, as the sodium salt, were given to 

 men. In one case a man of 59 kilograms 

 weight took 12 grams of the acid in 12 

 hours. All was excreted in combined form 

 and no increase of reducing substances in 

 the urine was noted. This amount of acid 

 is nearly one fifth of a gram per kilogram 

 of body weight, and is relatively less than 

 was ingested in many of the animal experi- 

 ments. If all combined with glycine it 

 would call for 7.38 grams of the latter, or 

 the glycine existing in about 200 grams of 

 mixed proteins. This amount is probably 

 more than was metabolized in the indi- 

 vidual in question. 



In another case of Lewinski 's a man 

 weighing 67 kilograms took 20 grams of 

 the acid in 12 hours. The urine examina- 

 tion showed the same result as in the other 

 case. Later, the same man took 25 grams 

 of the acid, but it was not all combined, 

 as 1.65 grams were recovered from the 

 urine. When the ingestion was increased 

 to 40 grams still more appeared in the 

 urine uncombined with glycine. In one 

 ease on the 40-gram dosage nausea and 

 headache were noted, but these effects 

 seemed less marked with a diet rich in 

 protein. The author concludes that on a 

 high protein diet more benzoic acid may be 

 ingested without ill effects. In one case a 



* Hofmeister's Beitraege, 7: 204. 

 ' Jaffe Festschrift, Braunschweig, 1901. 

 ' Milnch. Med. Wochensch., 52: 2168; Biochem. 

 Zeitschr., 6: 502 and 523. 

 ' Sehmied. Arch., 58 ■. 397. 



man took 50 grams without apparent dis- 

 turbance, but over 8 grams appeared in the 

 urine uncombined. 



All these experiments demonstrate that 

 in man, as well as in animals, ingested ben- 

 zoic acid may be detoxified in amounts 

 which much more than correspond to the 

 glycine of protein that may be metabolized 

 normally in the same individual, in the 

 same time. The 20 grams of benzoic acid 

 given in one experiment, and which left no 

 free acid in the urine, would correspond 

 to 12.3 grams of glycine. 



These papers have been cited because 

 they show the remarkable capacity of the 

 animal organism for the synthesis of hip- 

 puric acid and consequent disposition of 

 ingested benzoic acid. It has been shown 

 that the combining power of glycine is not 

 limited to that preformed, or which may be 

 split off in the ordinary metabolism, but 

 that in addition the potential glycine of 

 other amino groups is also available. 



It may be urged that this diversion of 

 potential glycine from more complex acids 

 is in itself an abnormal action, and there- 

 fore objectionable. This is possibly true, 

 and would have weight, if we were con- 

 cerned with the question of ingesting daily 

 5 grams or more of benzoic acid. But the 

 amounts to be practically considered are 

 so far below this that the question of break- 

 ing down extra protein does not come to 

 the front at all. 



What amounts of benzoic acid are actu- 

 ally in question here? Practically below 

 500 milligrams dailj^, if we consider the 

 ordinary solid or semi-solid foods, or below 

 a gram a day, if we consider certain bever- 

 ages sometimes treated with benzoate. 

 These are probably extreme figures, as for 

 the great majority of food substances ben- 

 zoate is not used or in any sense required. 

 What then is the physiological behavior of 

 these small amounts of benzoic acid which 



