EXPERIMENT STATION RECORD. 



Vol.41. Abstract Number. No. 3. 



RECENT WORK IN AGRICULTURAL SCIENCE. 



AGRICULTURAL CHEMISTRY— AGROTECHNY. 



Annual reports on the progress of chemistry for 1918, edited by J. O. Cain 

 and A., J. Geeenaway (Ann. Rpts. Prog. Cheni. [London], 15 (1918), pp. IX + 

 2JfO). — This is the usual annual report (E. S. R., 40, p. 109). Of special interest 

 to the agricultural chemist are notes on the progress in agricultural analysis 

 in the report on Analytical Chemistry by C. A. Mitchell, and the report on 

 Agricultural Chemistry and Vegetal)le Physiology by E. T. Russell. This re- 

 port includes advances in the chemistry of soil, fertilizers, plant growth, feed- 

 ing stuffs, milk, and fermentation. 



Studies relating to milk (New York Sta. Tech. Bui. 65 (1918), pp. 3-5Jt, figs, 

 /f). — This bulletin consists of three papers which have been previously noted 

 from other sources as follows: (1) The Preparation of Pure Casein, by L. L. 

 Van Slyke and J. C. Baker (E. S. R., 39, p. 801) ; (2) a Method for Making 

 Electrometric Titrations of Milk and Other Solutions Containing Proteins, by 

 J. C. Baker and L. L. Van Slyke (E. S. R., 39, p. 611) ; and (3) Free Lactic 

 Acid in Sour Milk, by L. L. Van Slyke and J. C. Baker (E. S. R., 39, p. 613). 



Preparation of rhamnose, E. P. Clakk (Jour. Biol. Cheni., 38 (1919), No. 2, 

 pp. 255, 256). — Satisfactory yields of rhamnose from quercitron extract are 

 said to be obtained by the following process: 



Two kg. of liquid quercitron extract is dissolved in enough hot water to 

 make 5.5 liters. To the boiling solution is gradually added 180 cc. of concen- 

 trated sulphuric acid dissolved in 320 cc. of water. After boiling gently for 30 

 minutes, the mixture is poured into an enameled kettle and cooled quickly. 

 The insoluble matter is filtei-ed off and the remaining liquid neutralized with 

 barium hydroxid and filtered. The filtrate is evaporated to a thin sirup, 8 

 volumes of 95 per cent alcohol are added slowly with constant stirring, and 

 the precipitate formed is filtered off on a Biichner funnel. The resulting fil- 

 trate is evaporated under diminished pressure to a thick sirup, dissolved in 1 

 liter of 95 per cent alcohol, and treated with 2.5 liters of ether. 



The gummy substance precipitated is separated from the supernatant liquid 

 by decantation, dissolved in 50 cc. of water and enough alcohol to make 1 liter, 

 and again precipitated with 2.5 liters of ether. The liquid is decanted and the 

 two ethereal extracts are mixed and allowed to stand over night. The clear 

 solution is poured from the gummy substance, the ether is recovered by distill- 

 ing on a steam bath, and the remaining alcohohc solution evaporated under 

 diminished pressure to a thick sirup. An equal volume of alcohol and some 

 ether are added and, upon scratching the flask or seeding, the rhamnose sepa- 



201 



