RECENT WORK IN AGRICULTURAL SCIENCE. 



AGRICTIITURAI CHEMISTRY— AGROTECHNY. 



Studies on malic acid. — I, The transformation of malic acid to sugar by 

 the tissues of the maple (Acer saccharinum), W. R. Bloob {Jour. Amer. Chem. 

 Soc, S/f {1912), Xo. //, PI). 53-'i-5S'.>). — With a view to detormiuiug whether the 

 tissues of the maple tree were capable of transforming malic acid into sugar, 

 tests were made with neutral calcium nialate obtained by twice recrystallizing 

 " sugar sand " acid calcium malate obtained by precipitating half the calcium 

 from the neutral malate by means of oxalic acid aud recrystallizing the product, 

 malic acid obtained by removal of all the calcium from the crude neutral 

 malate by oxalic acid (this product contained a small amount of cane sugar 

 as an impurity), and pure malic acid obtained by precipitation of all the calcium 

 from the neutral calcium malate. As it was believed That the transformation 

 would be greatest in those parts of the tree showing signs of life at the time 

 of the sap flow, viz, the swelling buds and shoots, aqueous extracts of these 

 parts were made and the malic acid preparations added. Blanks were also 

 prepared containing no malic acid, some solutions of the tissues were exposed, 

 to sunlight for certain periods of time, others kept in darkness, and other lots 

 of tissues extracted with water or boiled. The amount of acidity and sugar 

 was determined in each case. 



The results showed that with the shoot tissues mixed with malic acid or 

 malates and exposed to sunlight a diminution of acidity and an increase in 

 reducing substances took place. This was interpreted as a transformation of 

 malic acid into sugar. "A less pronounced change of the same kind is produced 

 in darkness at 38°. The active principle which produces the change is some- 

 what soluble in water, is destroyed by boiling, and is therefore probably of 

 enzym nature. The tissue of maple buds similarly treated brings about a de- 

 crease of reducing substance and an increase of acidity in solutions of malic 

 acid or its salts." 



The chemical composition of the substances contained in the birch, G. 

 Grassee {Collegium, 1911, Nos. 484, PP. 393-402; 485, pp. 405-412; 486, pp. 

 413-420; 487, pp. 421-425; abs. in Jour. Soc. Chem. Indus., 30 {1911), No. 24. 

 p. 1462). — The author treated the residue obtained from the alcoholic extrac- 

 tion of 2 kg. of leaves from the white birch {Betula alba) with cold alcohol, 

 ethyl ether, and dilute caustic potash solution and sulphuric acid, purified tho 

 constituents by further treatment, and observed their solubility in various 

 liquids, together with their behavior with various reagents. 



"The fraction of the extract dissolved by ether contained a wax-like, dark 

 green mass of a resinous character, soluble in petroleum ether, which was 

 found to have the composition C39Hgs02(OH)COOH, and yielded substitution 

 products with metallic salts of the typeC39H6302(OH)COO.Cu.COO(OH)02H6sC39. 

 The ethyl ester and also the acid chlorid and amid were prepared from it. By 

 oxidation with fuming nitric acid, butyric acid was produced. 



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