CHEMISTRY. 665 



condenser for 2 hours, or is extracted with boiling alcohol in a Soxhlet 

 extractor. The sugars extracted are determined either in the polar- 

 imeter, if only sucrose is present, or by titration with Fehling's solution 

 before and after inversion. The residue from tlie alcoholic extraction 

 is treated Avith oOO cc. of water for 18 to 24 hours with frequent agita- 

 tion, the a([ueous extract evai)orated to 200 cc, and an aliquot part 

 inverted with dilute acid and titrated with Fehling's solution. The 

 residue from the aqueous extract is brought to an air-dry condition, 

 weighed, and 2 gm. of the material boiled thoroughly with 100 cc. of 

 water for 3 minutes to gelatinize the starch. A malt infusion is pre- 

 pared by digesting 10 gm. of finely ground fresh malt with 50 cc. of 

 water at ordinary temperature, with frequent agitation for 2 to 3 hours. 

 The gelatinized starch is treated with 10 cc. of this infusion at a tem- 

 perature not exceeding 05° C. from 2 to 3 hours, or until the iodin 

 reaction disappears, when the solution is filtered on a linen filter and 

 thoroughly washed with hot water. The filtrate is evaporated to 100 

 cc. and treated with 10 cc. of concentrated hydrochloric acid at the 

 temperature of a boiling water bath for 1 hour, in order to convert the 

 malt sugar into dextrose, the solution neutralized, made to a volume of 

 200 cc, and titrated with Fehling's solution. The result is corrected 

 for the sugar introduced in the malt extract. The residue from the malt 

 extraction receives 100 cc of water and 2 cc. of strong hydrochloric 

 acid and is heated to boiling under a reflux condenser or in a water 

 bath for 1 hour, in order to convert the gums and pentosans into reduc- 

 ing sugars which may be regarded as xylose. The solution is filtered, 

 neutralized, made to 200 cc, and titrated with Fehling's solution. The 

 residue is treated with 1.25 per cent sodium hydroxid as in the Weende 

 method for crude fiber, and the remainder taken as crude fiber. 

 In conclusion the author says : 



"In many cases it is believed that the total amount of carbohydrates thns defi- 

 nitely determined in food materials will be found to be appreciably less than the 

 nitrogen-free extract estimated by dift'eience. If subsequent research should. justify 

 this belief, the character of this non-carbohydrate and non-nitrogenous substance 

 would remain to be determined. This question is now beiug investigated, and for 

 the present the writer desires to reserve the subject of inquiry to this laboratory. 



"This outline is thought to present an analytical method superior to anything 

 at present available for the estimation of carbohydrates in foods, although it can 

 not be regarded as in any sense perfected. It will have served its purpose if it shall 

 suggest to others the necessity of something better and assist them in the search 

 for it." 



The quantitative determination of carbohydrates in food stuffs, 



II, W. E. Stone {Jour. Amvr. Clicin. *S'oc., 1!J {1897), No. I,})}), o 17-319). — 

 In this paper the author gives the percentages of starch in maize, 

 wheat, flour, and bread, as determined by his revised method (see 

 above), and summarizes the determinations made of the different car- 

 bohydrates of these substances. The summary is given on the follow- 

 ing page : 



14780— No. 8 3 



