412 EXPERIMENT STATION KECORD. 



Substances in the crust of bread and in biscuits which, give the f'^rric 

 chlorid reaction, A. Hackk (Ann. J'alsif.. .> {lUU!)), Ao. IS. p. ')0i)).—Ou exani- 

 iiiiiiu (irdiiijiry brrnd c-nist and Iiiscnits the author finds that the same ferric 

 chlorid reaction is obtained as that with Nestle's milk Hour. 



Rice flour, K. Coli.in (Ann. Falsif., 2 {1909), No. I.>. i>i). ',.iS-.',3<.i, figs. 7).— 

 This is a discussion of the characteristics of rice Hour and methods for its 

 dettH.'tion in foods. 



The quantitative determination of cane sugar by the use of invertase, 

 C. S. Hudson {U. IS. Dcpt. Agr., Jim: Vhcm. Virc. 50, pp. 8, fig. 1). — The 

 author shows that invertase will hydrolyze cane sugar without notably affecting 

 other substances such as starch, dexti-in, maltose, pentosans, and natural glu- 

 cosids, and suggests its use for the determination of cane sugar. The method 

 proposed is as follows : 



" Dissolve 2G gm. of the substance to be analyzed for cane sugar in water, 

 clarify with the usual substances (neutral or basic lead acetate or alumina 

 cream or kaolin) and make up to 100 cc. volume at 20° C. Filter and read the 

 polarization of the filtrate, S, for a 200 mm. tube. Remove the excess of lead 

 from the filtrate, if lead has been used as clarifying agent, with sodium car- 

 bonate or potassium oxalate and filter. To 50 cc. of the filtrate add acetic acid 

 by drops until the reaction is acid to litmus, add 5 cc. of the stock invertase 

 solution and make up the volume to 100 cc. Add a few drops of toluene to the 

 solution to prevent the growth of micro-organisms, shaking so as to saturate, 

 and allow to stand at any temperature between 20 and 40° overnight. Under 

 usual conditions about 6 hours' time is required to accomplish complete hydro- 

 lysis. In the morning bring the temperature to 20° and read the rotation of 

 the solution, I, for a 400 mm. tube. The percentage of cane sugar present is 



S-I 

 then calculated by the formula : Per cent of cane sugar= ■. ., y_TxiOf)," where 



S is the direct reading of the solution, I the reading of the inverted solution, T 

 the temperature, and 141.7 the inversion constant. 



Directions for the preparation of the invertase solution, which is made from 

 baker's or brew'er's yeast, are given. Its rotation was 1.0° V in the 400 mm. 

 tube. It was dextrorotary. 



New procedure for determining sugar by Bonnan's method, P. Maillard 

 (Ann. Chim. Anulyt., /.) (lUO'J), No. 9, pp. 3-'i2-3.',8 : ahs. in Analyst, 3.', (1909), 

 No. .'lO'i, p. 500). — This is a description of a procedure which is supposed to in- 

 sure against possible discrepancies due to improi)er conditions of ebullition. 

 The author has comi)iled a table in which the time relation for the titration is 

 considered. 



A delicate reaction for sugars, Pozzi-Escot (Bui. Assoc. Chim. Sucr. et 

 Distill., 27 (1909), No. 3, pp. 179, 180; abs. in Chem. Ztg., 33 (1909), No. 126, 

 Repert., p. 538). — If 1 cc. of a 5 per cent ammonium molybdate solution is 

 mixed with 2 cc. of a cane sugar solution (over 0.000.5 per cent) and a contact 

 test made with 10 to 12 cc. concentrated sulphuric acid, a blue colored ring is 

 obtained within 20 minutes. If the upper portion of the mixture is heated to 

 the boiling point, as little as 0.(X)002 per cent of sugar can be detected within 30 

 minutes. 



Clarification of solutions containing invert sugar, C. A. Browne, A. H. 

 Bryan, and H. W. Wiley (Ztschr. Ver. Deut. Zuckerindus., 1909, No. Sj^S, II, pp. 

 922-932; abs. in Chem. Ztg., 33 (1909), No. 126, Repert., p. 5.',3).— It is concluded 

 from these investigations that for lead vinegar neutral lead acetate should be 

 substituted. It is advisable to control the purity of the latter by determining 

 its lead content by both the specific gravity and the usual analytical method. 



