POODS HUMAN NUTRITION. 63 



of the American Society of Biologiciil Chemists. The experiments reported 

 confirm the results of earlier investigators and also show that starving and 

 diabetic animals may retain a considerable part of the nitrogen ingested as 

 ammonium carbonate. 



Concerning' purin metabolism in man. — I, Are the pnrin bodies interme- 

 diate or terminal metabolic products? V. O. Siven {P finger's Arch. Physiol., 

 JJ/S (1912), No. 5-6, pp. 2S3-297). — As a result of original experiments on 

 normal subjects, the purin content of whose diet was carefully regulated, the 

 author holds that the purin bodies excreted by the human organism are termi- 

 nal products. 



A large part of the exogenous pnrins ingested with the food undergoes con- 

 siderable alteration in the digestive tract. Part is resorbed, together with 

 the purin nuclei, and undergoes no further transformation, but is given off 

 from the kidneys in the form of purin bodies in a comparatively short time 

 (from 12 to 15 hours). The reason that purin bodies, whether exogenoTas or 

 endogenous, which enter the circulation, uudergo no further alteration, such 

 as would break the purin cycle, is that the hiunan organism lacks uricolytic 

 power. 



Concerning purin metabolism in man. — II, Are the endog'enous jsurin 

 bodies products of the activity of digestive secretions? V. O. Siv^n (PflAger's 

 Arch. Physiol, IJfS (1912), No. 10-12, pp. 499-516; abs. in Ghem. ZentU., 1912, 

 II, No. 9, p. 782). — A controversial article. See also above. 



Transformation of sugars in the human organism, J. Paenas and J. Baer 

 (Biochetn. Ztschr., J^l (1912), No. 5, pp. SS6'-4i8).— It is stated that the 

 chemical processes by which the transformation of the glucose molecule into 

 carbon dioxid and water take place have not yet been explained. Only lactic 

 acid has been determined as an intermediate product of the metabolism in the 

 muscles. 



It has been assumed by some that the transformation of lactic acid to glucose 

 is simply an inversion of the same process. If this means that the reaction is 

 one of chemical equilibrium, the author is unwilling to admit this view, partly 

 because it is unsupported by evidence, and partly because it may involve admit- 

 ting the possibility of a reversible action in enzyms. But, if it were possible 

 to show a series of intermediate changes in the transformation of lactic acid 

 to glucose, the opposite of those demonstrated in the transformation of glucose 

 to lactic acid, the reaction could be considered one of oxidative disintegration. 

 Such an assumption would clarify certain practical points, such as the ability 

 of a muscle to work without oxygen but not to restore itself, or the excretion 

 of lactic acid in cases of poisoning by phosphorus or arsenical substances 

 which interfere with the normal metabolism, and cause an unusual disintegra- 

 tion of glucose or glycogen. It may also indicate the mechanism by which the 

 neutrality of body substances is maintained. 



Transformations of the carbohydrates in the animal organism, J. Paenas 

 (Miinchen. Med. Wchnschr., 59 (1912), No. 32, p. 1788; abs. in Med. Rec. 

 [N. r.], 82 (1912), No. 10, p. 437). — A continuation of the above discussion. 



Studies on the formation of glycocoll in the body, II, A. A. Epstein and 

 S. Bookman (Jour. Biol. Chem., IS (1912), No. 2, pp. 117-131).— Free leucin 

 administered with benzoic acid was decomposed in the body but did not yield 

 glycocoll. Benzoyl leucin with benzoic acid increased the production of hip- 

 puric nitrogen to a greater extent than the leucin radical of the compound alone 

 could furnish, which was due in part to the leucin i^dical and partly to the 

 independent action of the benzoyl radical. The increase in production of 

 glycocoll observed in fasting animals poisoned with phosphorus and given benzoic 



