AGRICULTURAL CHEMISTRY. 307 



stitute the molecules of the different proteins. "As we have hut little knowledge 

 of the relative proportious of these amino acids in the proteins burned, we are 

 not able yet to draw any definite conclusions in regard to these differences." 



Changes in the index of refraction of glucosids and proteids induced by- 

 ferments, acids and bacteria, F. Obermayeb and E. P. Pick (Beitr. CUrin. 

 Phiixiul. II. Pnth.. 7 il9<>'>). jip. SSl-S.-^n : ahs. hi Hifij. Riiiidschuii.. 17 (lO'iH. 

 \ii. n. p. ooS). — Experiments undertaken by the authors showed that determin- 

 ing the refractive index of glucosids and proteids afforded a satisfactory method 

 of studying the molecular changes brought about by cleavage agents. 



Sucrase in apple pomace and cider, G. Warcollieb {Cowpt. Rend. Acnd. s<-i. 

 [Paris]. 14^ (1901), Xo. 18, pp. 9S7-990). — Experimental data showed, in the 

 author's opinion, that sucrase is not present in apple pomace and that iiomace 

 rich in sawharose ferments as rapidly as that which contains small quantities. 

 Th.' iinersion of saccharose in cider is brought about by the sucrase of yeast. 



The determination of nitrates by the Busch method, R. Adax (Bnl. Sor. 

 Chim. Belg.. 21 {1901). Xo. 6. pp. 229-233 : abs. in Jour. Cheiii. Sor. [Loitdoin..92 

 (1901). yo. o3S. II. pp. 651, 652). — The method of determining nitrates by 

 precipitation with nitron is described and tests of the method on various samples 

 of nitrate are reported. The results obtained by this method agreed closely 

 with the calculated percentages. Studies of the solubility of the nitron pre- 

 cipitate are also reported, solubilities of from 1.35 to 2.23 per cent, as a result 

 of prolonged washing, being found. The presence of nitrites was found to be 

 a serious source of plus error. It is stated that a great obstacle to the general 

 use of the method is the high price of the reagent. 



On methods of determining soluble phosphoric acid in slag, E. .Jextys 

 (Siir les Methodcs de Dosage de I'Acide Phosphorique Soluble dans les Seories. 

 Cracoir: Imprimerie de VUniversite Jagellone, pp. 21). — The author discusses 

 sources of error in the citric-acid method without separation of silica, as 

 proposed by Wagner, and with separation of silica, as proposed by Loges. 

 and reports comparative tests of these methods on 388 samples of slag of differ- 

 ent kinds. He found that the Loges method gave uniformly lower results than 

 the Wagner method, the average difference for all of the samples examined 

 being (1.25 per cent. The conclusion is reached that neither of the methods is 

 entirely satisfactory. 



Methods of analysis and tests used by the chemists, P. A. Yoder {I'tah .s7«. 

 Bui. 102. pp. 229-231 ) .—Methods of treating air samples and determining the 

 carbon dioxid and moisture content are described, which were used in the incu- 

 bation experiments noted elsewhere (p. 3<)S). 



The determination of creatin and creatinin, F. G. Benedict and V. C. 

 Myers (Anier. .lour. Phi/sioL. IS (1901). Xo. ',. pp. 397W,r^5).— But little regu- 

 larity can be observed in the properties of creatin and creatinin in human 

 urine. 



According to the authors' deductions from the experimental data reported, 

 " in general the conversion of creatinin to creatin seems to be due to chemical 

 action, or possiblj' to the action of enzyms in the urine. When a urine is 

 allowed to stand, alkaline fermentation takes place, and the creatinin sooner 

 or later almost completely disappears. Furthermore, the evidence from alkaline 

 urines is not conclusive to show that creatin is an intermediate product. The 

 <f>nversion of creatinin to creatin even in the presence of chloroform and thymol 

 shows that this c-onversion is not a bacteriological process. It is obvious that 

 much experimenting must l)e carried out before the problem is wholly clarifieil. 

 In general it would appear that there is more likely to be a complete loss of 



