214 



SCIENCE 



[N. S. Vol. XLIV. No. 1128 



The precipitated sulfur from either titration may 

 be weighed directly. A quick accurate method of 

 weighing it is described. 



It is shown that H,S may be removed from a 

 slightly acid solution by boiling without decom- 

 posing thiosulfate, also that tetrathionate is eon- 

 verted into thiosulfate by an excess of soluble 

 sulfid, the latter decomposed with HC1, the H 2 S re- 

 moved by boiling and the thiosulfate titrated. 



Sodium nitroprusside may be used as internal 

 indicator. 



Some Studies on Liquid Fertilizer : G. D. Beal and 



D. T. Englis. 



The Detection of Lime used as a Neutraliser in 

 Dairy Products: H. J. Wichman. 



DIVISION OP BIOLOGICAL CHEMISTRY 



C. L. Alsberg, Chairman 

 I. K. Phelps, Secretary 

 The following papers were read by title: 



Mutarotation of Gelatine and its Significance in 

 Gelatin: C. E. Smith. 



Chemical Studies on the Decomposition of Bed Oak 

 by Fomes applanatus and of Bed Spruce by 

 Trametes pini var. abietis: E. J. Piper, C. J. 

 Humphrey and S. P. Acree. 



Some Observations on the Bacterial Metabolism of 

 Sulfur Compounds: F. W. Tanner. 



A Study of the Ethereal Sulphates of the Urine in 

 Certain Chronic Diseases: J. Eosenbloom. 



The Ammonia Content of Human Gastric Juice : J. 

 Eosenbloom and Jena Miltan. 



Some Auxoamylases : E. W. Eockwood. 



The Non-Protein Constituents of Foods and Feed- 

 ing Stuffs : H. S. Grindley and H. C. Eckstein. 



Swine Feeding Experiments to determine the Nu- 

 tritive Value of the Amino Acids: J. C. Eoss. 



Further Observations on the Surface Tension of 

 Saponin Solutions: C. L. Alsberg and H. E. 

 Woodward. 



The Changes in the Amino-acid Nitrogen and Sol- 

 uble Non-protein Nitrogen: E. S. Potter and E. 

 S. Snyder. 



Diet in its relation to the Treatment of Diabetes: 



E. E. BUTTEREIELD. 



The Nitrogen Distribution in Certain Seeds: C. L. 

 Alsberg and F. Brewster. 



Phospholipid, Lecithin, Cephalin and Similar Sub- 

 stances: M. Louise Poster. 



The Fate of Methylene Disalicylic Acid and De- 

 rivatives in the Body: E. A. Hall and E. D. 

 Brown. 



The Pharmacological Action of Citrates: E. A. 

 Hall and E. E. Morris. 



On the Esterfication of Amino Acids: H. H. 



Shonle and H. H. Mitchell. 

 Digest of Data on Mineral Substances in Diet: 



Grace MacLeod. 

 The Temperature of Potatoes while Cooking and 



a Method of Measuring Temperature during 



Cooking and Canning: E. D. Milner. 

 The Organic Phosphorus of Soil : E. S. Potter and 



T. H. Benton. 

 The Chemical Aspect of Photosynthesis in Plants: 



H. A. Spoehr. 

 The Growth of Isolated Plant Embryos: G. D. 



Buckner and J. H. Kastle. 

 A Chemical and Bacteriological Study of some 



Non-Pathological Gastric Besiduums: C. C. 



Fowler, M. Levine and S. B. More. 

 A Study of Eighty Samples of Gastric Besiduums 



Obtained from Apparently Normal Women: C. 



C. Fowler and Z. Zentmire. 



Belative Sensitivity of Some Commercial Litmus 

 Papers: Arno Viehoever and Clare O. Ewing. 

 Blue, neutral, red litmus papers from nine Amer- 

 ican manufacturers and one foreign manufacturer 

 were found to vary in sensitivity within very wide 

 limits. Best results were obtained when the ' ' blue ' ' 

 papers were of a dull or grayish blue color; the 

 ' ' neutral, ' ' a dull lavender or pinkish- violet ; and 

 the ' ' red, ' ' a light pinkish red. It is considered 

 that good papers should respond quickly to 2V/500 

 acid or alkaline solutions. 



By means of a " spot test, ' ' in which one or more 

 drops of the solution to be tested were superim- 

 posed on the test paper, thus in effect concentrating 

 the solution, the reaction of solutions as dilute 

 as JV/25,000 (1:500,000) HcS0 4 and IV/2,000 

 (1: 50,000) NaOH could be determined. 



On the Determination of the Digestibility of the 

 Constituents of a Mixed Diet: H. H. Mitchell 

 and H. S. Grindley. 



A method of determining the digestibility of the 

 constituents of a mixed diet is proposed, based on 

 the product-moment method of correlation. The 

 daily intake of nitrogen from each food ingested is 

 correlated with the daily excretion of nitrogen in 

 the feces. Coefficients or regression of fecal nitro- 

 gen on each type of food nitrogen are then calcu- 

 lated, giving figures representing the average in- 

 crease of fecal nitrogen for an increase in intake 

 of 1 gram in meat nitrogen, bread nitrogen, etc. 

 From these coefficients, the digestibility of the 

 nitrogen of each of the foods ingested may be cal- 

 culated. The digestibility of the fat, phosphorus, 

 chlorine, etc., of the individual foods may be cal- 

 culated in a similar fashion. 



