ANIMAL PRODUCTION. 369 



elimination of pnrin bases. The smaller and lighter of the two subjects ex- 

 creted, in every case, a larger percentage of uric acid and purin bases than the 

 other subject, and, according to the authors, " may possess a more limited 

 power for uric acid destruction." 



The effect of meat purins (largely free hypoxanthiu), on the elimination of 

 purin compounds is illustrated by data cited from a series of experiments by 

 Hilditch, also made at Yale University, in which meat was substituted for 

 the milk and eggs of a puriu-free diet. The resulting increase in the excre- 

 tion of uric acid nitrogen, it is stated, is quite comparable with the figures 

 obtained in the experiment with pure hypoxanthiu. 



In discussing their work in comparison with that of earlier investigators, the 

 authors point out that the data which they report " emphasize the fact that all 

 of the familiar purins may lead to an increase in exogenous uric acid in the 

 urine of man, with (quantitatively) little influence on the elimination of the 

 jiurin bases. They may be interpreted to support the most preA'aleut view that 

 uric acid is a stage in the metabolism of exogenous purins in the human body, 

 a view rendered especially plausible by the growing statistics on tissue enzyms. 

 The inequalities in the quantitative aspects of this uric acid production are 

 striking, a far larger proportion of uric acid being eliminated after ingestion 

 of hypoxanthiu and xanthin than after the amino purins. We may call atten- 

 tion to the absence of any further metabolic disturbance associated with the 

 introduction of the purins in the doses used. They did not act conspicuously 

 as diuretics. The absence of any marked perversion of nitrogenous metabolism 

 and the uniformity of the conditions observed is attested by the constancy of 

 some of the urinary features, notably the endogenous creatinin elimination, 

 and the figures for ammonia nitrogen and phosphorus. . . . 



" It will be noted in our protocols that an increased output of uric acid was 

 attained just as well by feeding pure hypoxanthiu as through the agency of 

 the extract of meat with its hypothetical ' tf>xins.' " 



The effect of muscular work upon animal organs, particularly their water 

 content, H. Gerhartz {Pfliiger's Arch. Physiol., 133 {1910), No. 7-10, pp. 397- 

 'i99, Ogm. 1). — According to the author's conclusions, from experiments with 

 dogs, muscular work increases the renal excretion and consequently the excre- 

 tion of sodium chlorid and water. The heat produced by muscular work is 

 chiefly eliminated by the evaporation of water, only about one-fourth leaving 

 the body by radiation and convection. Under the experimental conditions, the 

 water taken after work did not fully comjiensate for that excreted, so that the 

 organism had a lower water content as a result of work. Increased dry matter 

 content is the principal characteristic of muscle hyperti'ophy due to muscular 

 work. Other conclusions are also presented. 



The influence of mental and muscular work on nutritive processes, F. G. 

 Benedict (Proe. Amer. Phil. /S'oc, 49 (1910), No. 195, pp. lJf5-163, ffgs. 3).— 

 The experiments summarized have been reported in a bulletin of the Office of 

 Experiment Stations (E. S. R., 21, p. 68). 



ANIMAL PRODUCTION. 



Investig'ations on the utilization of ammonium salts and the nonprotein 

 nitrogen compounds of feeding' stuffs, A. Mokgen, C. Beger, and F. West- 

 HAUSSER {Landic. Vers. Stat., 73 {1910), No. 4-5, pp. 285-394).— Thef^e investi- 

 gations were continued with some slight modifications along the lines pre- 

 viously noted (E. S. R., 21, p. 666). Analyses are given of the basal rations, 

 which consisted of hay, dried beet chips, and straw, supplemented at times by 

 dried slop, starch, sugar, and peanut oil. 



