RECENT WORK IN AGRICULTURAL SCIENCE. 



AGRICULTURAL CHEMISTRY— AGROTECHNY. 



Sulphite method for separating and identifying calcium and strontium, 

 J. I. D. Hinds (Jour. Amcr. Chetn. Soc, 33 (1911), No. Jf, pp. 510-514).— This 

 is a qualitative method, based on the fact that sulphite of strontium is only 

 slightly soluble in water while sulphite of calcium is exceedingly so. 



[In regard to methods for determining the fertility of the soil, particu- 

 larly in reference to phosphoric acid], B, Welbel (Godichnyi Otchet Ploti. 

 Selsk. Khoz. Opytti. StantsU, 15 (1909), pp. 167, 168).— The methods which use 

 weak solutions of organic acids for this purpose are not recommended, as such 

 solutions often become infected. The use of antiseptics in this connection 

 affects the results for nitrates and soluble phosphates, and, furthermore, inter- 

 feres with the analysis of the other substances in the same solution. The 

 employment of dilute mineral acids (such as 5 cc. of nitric acid, specific gravity 

 1.4, to 5 liters of distilled water) is preferred by the author. 



Detection and determination of manganese in water, J. Rodenbueg (Chem. 

 WeekU., 7 (1910), No. 4I, pp. 877-879).— The method is as follows: 



Fifty cc. of water is boiled for a few minutes with 5 cc. of a 50 per cent 

 solution of nitric acid, enough silver nitrate solution is added to remove the 

 chlorids present (but avoiding a large excess), and finally 10 cc. of a 10 per 

 cent solution of ammonium persulphate. The solution is then heated to the 

 boiling point. If manganese is present, even in amounts as small as 0.025 mg. 

 (MnsOi), the solution will assume a pink or red coloration. 



If a quantitative determination is to be made, the above solution is filtered 

 into a colorimeter tube and compared with other tubes of distilled water con- 

 taining known amounts of manganese-ammonium sulphate. 



The determination of arsenic in insecticides, E. B. Holland (Massachusetts 

 Sta. Rpt. 1910, pt. 1, pp. 122-130). — Previously noted from another source 

 (E. S. R., 25, p. 615). 



A method for studying chemical cell functions and the results obtained 

 with it, M. Hahn (Miinchen. Med. Wchnschr., 58 (1911), No. 20, pp. 1385- 

 1388). — A method is described which uses the Buchner press for obtaining an 

 extract of the substance in question and dialysis through parchment paper. 

 Tests with it and gland extracts, such as those from the mammary gland and 

 pancreas, and the milk, are reported. 



It was noted that after dialyzing extracts of the mammary gland and pan- 

 creas an increase ia reducing substances (detected with Fehling's solution) 

 takes place, which points to the possible presence of pro-substances. In the 

 case of the mammary gland the author points out the necessity of studying the 

 subject further, in order to determine if this increase in reducing bodies is due 

 to either lactose or pentose formation. 



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