1918.] AGRICULTURAL CHEMISTRY AGROTECHNY. 50? 



are given of the manganese content of certain laxative drug plants. It has 

 been found that for the family Rhamnacefe the manganese is extracted by 

 uater proportionately to its total amount in the bark. 



The inversion and determination of cane sugar, A. R. Rose (Proc. Soc. 

 Expt. Biol, and Med., 15 {1911), No. 2, pp. 16, 17).— The use of picric acid in 

 the inversion and determination of cane sugar in solutions and extracts is 

 described as follows : 



One cc. of the clear liquid containing the sugars is transferred to each of two 

 graduated test tubes containing 2 cc. saturated solution of picric acid. To one 

 of the tubes is added 1 cc. of 20 per cent sodium carbonate. The two tubes are 

 heated for 10 minutes in a bath of boiling water. The same amount of sodium 

 carbonate Is added to the second tube and the heating of both tubes continued 

 for 30 minutes. The tubes are cooled and the contents diluted to a suitable 

 volume and matched against a standard solution in a colorimeter. The dif- 

 ference in the readings of the two tubes represents the invert sugar from the 

 sucrose. 



In applying this method to solids, such as mashed fruit pulps, from 1 to 

 10 gm. are taken and triturated in a mortar with 100 cc. of water and a clear 

 liquid obtained by filtering and centrifuging. 



It is suggested that picric acid may also be used as the inverting agent in the 

 determination of cane sugar by polarizing. It has no effect on polarized light 

 and in some cases acts as a clarifier and remover of soluble proteins. 



The preservation of plant juices for analysis of sugar content, D. O. 



Speiesterseach {Jour. Avier. Chem. Soc, IfO {1918), No. 2, pp. .'f31-.'f.3G) . In 



the course of sorghum investigations at the Minnesota Experiment Station the 

 author examined the action of different preservatives on plant juices to pre- 

 vent fermentation and hydrolysis of the sugars and at the same time not to 

 interfere with the proper determination of the composition of the juice. 

 Toluene and mercuric potassium iodid were both tested. The latter apparently 

 possesses the greater preserving power. Both showed the maximum effect in 

 boiled samples which had been rendered slightly alkaline with sodium car- 

 bonate. From 0.05 to 0.1 per cent potassium mercuric iodid was u.sed or 

 sufficient toluene to saturate the solution. 



Preliminary investigations with mercuric nitrate have indicated that it may 

 be even more effective than mercuric potassium iodid. 



Home canning of meats {Okla. Agr. Col., Ext. Div. Circ. 63 {1911), pp. 8). — 

 This circular gives a list of materials necessary for the successful home canning 

 of meats and general directions for the preparation of meat and for filling and 

 cookstove driers and portable evapoi'ators is included. 



How to dry fruits and vegetables for home consumption, C. D. Matthews 

 (A''. C. Agr. Ext. Serv. Circ. 50 {1911), pp. U/, fig. 1). — The author has compiled 

 the available information on the different methods of drying fruits and 

 vegetables, varieties of driers, and related topics. Detailed directions for the 

 drying of certain vegetables and fruits are given, and a list of firms making 

 cookstove driers and portable evaporators is included. 



Action of manganese sulphate in wine fermentation, J. B. Laba {Proc. 2. 

 Pan Amer. Sci. Cong., 1915-16, vol. 8, pp. 839-84-3). — The investigations reported 

 show that the addition of manganese sulphate to grape must causes a greater 

 multiplication of yeast. The optimum proportion to be added is 0.005 gm. of 

 the sulphate per liter. A larger amount causes the consumption of all the 

 fermentable sugar by the yeast, imparting to the wine a less agreeable ta.ste. 

 The wine obtained after the addition of manganese sulphate contains no higher 

 percentage of alcohol but has a more aromatic flavor. 



