RECENT WORK IN AGRICULTURAL SCIENCE. 



CHEMISTRY 



Sulphuric acid as a reagent in the analysis of fatty acids, E. 

 Twitchell {Jour. Soe. Ghem. Ind., 16 {1897), No. 14, pp. 1002-1004).— 

 The reaction between concentrated sulphuric acid and any fat involves 

 chiefly the unsaturated fatty acids of the fat and consists primarily of 

 the addition of sulphuric acid to the unsaturated carbon atoms of these 

 acids. On this assumption the author concluded that a separation of 

 the unsaturated oleic, linoleic, and linolenic acids from the unattacked 

 saturated palmitic and stearic acids could be made and possibly a dif- 

 ference in the action of sulphuric acid in the different members of the 

 group of unsaturated acids might then be shown. The following ten- 

 tative method was adopted: Weigh from 0.5 to 1 gm. of the fatty acid 

 in a glass stoppered Erlenmeyer flask; melt and allow to solidify in as 

 thin a layer over the bottom as possible. On the layer pour about 3 cc. 

 of 85 per cent of sulphuric acid. There is usually no combination until 

 the flask has been slightly warmed. At a certain temperature the com- 

 bination takes place very rapidly and forms a clear solution. When 

 this occurs the flask is quickly cooled, 50 cc. of petroleum ether added, 

 the stopper inserted, and the flask shaken violently for a minute or two, 

 then allowed to settle and the petroleum ether decanted. The flask 

 is rinsed twice with 10 cc. of petroleum ether, the washings added to 

 the first extract, and the whole poured into a separatory funnel and 

 washed once or twice with water. The petroleum ether is then evapo- 

 rated, and the residue, consisting of the saturated fatty acids, is 

 weighed. — j. p. street. 



Needed reform in the analytical methods for fodders and feeds, 

 E. Schulze {Landtv. Vers. Stat., 49 {1898), No. 6, pp. 419-441).— The 

 author calls attention to the impurity of the ether extract obtained 

 from feeds in the ordinary analysis and the inaccuracy of the methods 

 for crude fiber. None of the present methods for fiber are accurate 

 for all classes of fodders and feeds. He suggests that after the material 

 is dried and finely pulverized it be extracted with ether, alcohol, malt 

 extract, and water. This will bring into solution the fats, lecithin, 

 soluble carbohydrates, starches, amids, soluble proteids, etc. The 

 insoluble residue will consist of the insoluble proteids, the cell walls, 

 and a part of the ash constituents. By determining and deducting 



115 



