396 



SCIENCE 



[Vol. LVI, Xo. 1449 



a galvanometer as an iudieator. Two atoms of 

 bromine are required for each molecule of fur- 

 fural. Laevulnic acid and hesoses do not inter- 

 fere in the estimation of pentose material by its 

 conversion first into furfural and the subsequent 

 titration. 



Methods for the estimation of total solids and 

 hydrophilic colloid content of expressed plant 

 tissue fluids with certain phytochemical applica- 

 tions. Boss Aiken Goetner, Eobekt Xewton 

 and Walter F. Hoffman. The refractive index 

 of a plant sap as measured by an Abbe refraeto- 

 meter may be used to measure quantitatively the 

 total solids present in the sap. A measurement 

 of "bound water" is used to estimate the 

 liydrophiKe colloid content. The depression of 

 the freezing point of the original sap is obtained. 

 Then a quantity of sucrose just sufficient to make 

 a molar solution iu the total water present is 

 added and the depression of the freezing point 

 is again obtained. The excess depression (over 

 the theoretical 2,085 due to molar sucrose") is due 

 to a part of the water being held by the hydro- 

 philic colloids in such a manner as to be unavail- 

 able for the solution of sucrose. 



The origin of the humin formed hy the acid 

 hydrolysis of proteins. VII. Hydrolysis in the 

 presence of Icetones. Eoss Aiken Gortner and 

 Earl R. Norris. Ketones do not appreciably 

 alter the nitrogen distribution of a protein as 

 measured by Van Slyke's method. No evidence 

 was obtained that ketones could be involved in 

 humin formation. We believe, therefore, that 

 humin formation is caused by the interaction of 

 trj-phophane and an aldehyde. 



The tyrosine content of diaminized casein. 

 H. B. Lewis and Ealph C. Corley. 



The influence of food on the excretion of en- 

 dogenous Mric acid in man. (By title.) H. B. 

 Lewis and Ealph C. Corlet. 



The synthesis and rate of elimination of liip- 

 puric acid in the organism of the rahhit. H. B. 

 Lewis and Wendell H. Griffith. 



The analysis of the urine as a part of the 

 pliysical examination of the college student. G. 0. 

 HiGLEY. This work was begun in 1915 because of 

 the death of a college student from diabetes. 

 Tests are made for sugar and for albumin, and 

 in special cases for other pathological substances. 

 Each year a considerable number of cases of 

 nephritis are discovered, of which about two 

 thirds show a previous liistory of an acute attack 

 of that disease. When any pathological sub- 

 stance is detected a second and often a third 

 sample of urine is tested, and the student is ad- 



vised to consult a competent physician and to 

 report his findings to the college physical ex- 

 aminer. 



Further observations on the influence of vitamin 

 B on the development of organs in Single Cornl) 

 White Leghorn cocherels. Arthur J. Scuba and 

 E. Adams Dutcher. Six hundred and nine 

 chicks were hatched from eggs of pure line stock 

 and placed on a normal chick ration. At the 

 age of 76 days 150 normal cockerels were selected 

 and divided iu three groups, designated A, B 

 and C. Group A received a normal ration with 

 greens, Group B received an adequate synthetic 

 diet and Group C received a synthetic diet, ade- 

 quate in all particulars except vitamin B. After 

 four weeks 25 birds in each group were killed 

 and weights and measurements recorded on testes, 

 heart, kidneys, spleen, pancreas, liver, thyroid 

 and suprarenals. The remaining birds were 

 allowed to continue until polyneuritis developed 

 iu Group G, at w-hich time one bird from Groups 

 A and B, including the polyneuritic bird, were 

 killed. All data were treated biometrically. The 

 absence of vitamin B produced significant losses 

 in the weight of testes, heart, liver and kidneys. 

 Differences in length of heart and spleen were 

 also apparent. 



Is 7iitrogen in gaseous form lost from germina- 

 ting seed and young seedlings as an inherent func- 

 tion of their metabolic processes.' Jehiel David- 

 son. 



Influence of lysine upon the hydrolysis of 

 starch by purified pancreatic amylase. H. C. 

 Sherman and Mary L. Caldwell. This is an 

 extension of the work with arginine, histidine 

 and tryptophane ^vhich was reported by the same 

 authors last year. Lysine resembles histidine and 

 tryptophane in not increasing the amyloclastic 

 activity of pancreatic amj-lase while both lysine, 

 and tryptophane do increase its saccharogeiiic 

 activity. These results are best intei-preted in 

 terms of the theory that the favorable influence 

 of amino acids is attributable to their eilect in 

 checking the hydrolytic destruction of the enzyme 

 iu the aqueous dispersions in which it acts. The 

 theoretical part of the paper does not lend itself 

 to fnrtlier condensation. 



Influence of some organic compounds upon the 

 hydi-oh/sis of starch by salivary and pancreatic 

 amylases. H. C. Sherman and Nellie M. 

 Xaylok. In order to test the question whether 

 tlie organic substances, which have been reported 

 as favoring the activity of amylases, have a 

 directly activating effect upon the enzyme by 

 reason of their organic groupings, experiments 



