AGRICULTURAL CHEMISTRY AGROTECHNY. 807 



(2) agar (1 per cent), gel 50 gm., cane sugar 20 gm. ; (3) apple jelly; (4) 

 apple jelly 8 parts, agar gel (agar 2i, sugar 50, water 47^ i)er cent) 2 parts; 

 (5) apple jelly 6 parts, agar gel with sugar 4 parts; (6) gooseberry jelly; 

 (7) apples 53 parts, and gooseberries 12 parts; (8) starch; (9) gelatine; 

 (10) orange marmalade; and (11) currant jelly. The reagents used were 

 potassium iodid and a cold saturated solution of lead nitrate. About 5 per 

 cent of potassium iodid was added to the heated jelly, followed on cooling by 

 the lead nitrate solution. 



The lead iodid precipitate produced was found to vaiy in structure with the 

 material tested. Its structural characteristics can best be studied with the 

 microscope, although the differences can be noted macroscopically. Sugar 

 when present seemed to influence considerably the size of the lead iodid 

 granules produced. Emphasis is placed on the fact that much work will have 

 to be done in this direction and that the experimental data should be ac- 

 companied by photographs for the purpose of determining the utility of the 

 method for food inspection work. 



A method for the determination of starch in food products, T. M. Price 

 (U. S. Dept. Agr., Bur. Anim. Indus. Circ. 203, pp. 6). — This is a combination 

 of the desirable features pi-esent in the Perrier and the Bigelow-Mayrhofer 

 methods, and the elimination of the objectionable features contained in them. 

 The method is as follows: 



" In a 200 cc. beaker treat 10 gm. of finely divided meat with 75 cc. of an 

 S per cent solution of potassium hydrate in 95 per cent alcohol, and heat on 

 the steam bath until all the meat is dissolved. This will require from 30 to 

 45 minutes. Add an equal volume of 95 per cent alcohol, cool, and allow to 

 stand at least 1 hour. Filter by suction through a thin layer of asbestos 

 in a Gooch crucible. Wash twice with warm 4 per cent potassium hydrate 

 in 50 per cent alcohol and then twice with warm 50 per cent alcohol. Dis- 

 card the wash water. Endeavor to retain as much of the precipitate in the 

 beaker as possible until the last washing. Place the crucible with contents 

 in the original beaker, add 40 cc. of water and then 25 cc. of concentrated 

 sulphuric acid. Stir during the addition of the acid and see that the acid 

 comes in contact with all the precipitate. Allow to stand about 5 minutes, 

 add 40 cc. of water, and heat just to boiling, stirring constantly. Transfer 

 the solution to a 500 cc. graduated flask, add 2 cc. of a 20 per cent aqueous 

 solution of phosphotungstic acid, allow to cool to room temperature, and make 

 up to mark with distilled water. Filter through a starch-free filter paper, 

 and determine the dextrose present in a 50 cc. portion of the filtrate with 

 Fehling's solution after neutralizing the acid, using Low's method . . . for 

 the determination of the copper in cuprous oxid precipitate. The amount of 

 dextrose multiplied by 0.9 gives the equivalent in starch. 



" The accuracy of the above-described method was demonstrated through 

 its application to a number of samples of sausages to which known amounts 

 of pure cornstarch had been added." 



Determination of nucleic acid in the flesh of mammalia, A. Scala {Ann. 

 Ig. Sper., n. ser., 20 (1910), No. //, pp. 509-520; abs. in ZentU. Biochem. u. 

 Biophys., 13 (1912), No. 1-2, p. 9). — ^The method rests upon the principle that 

 when nucleic acids are treated with barium chlorid a precipitant of barium 

 nucleinate is obtained. 



Composition of dry gluten and its relation to the protein content of flour, 

 G. A. Olson (Jour. Indtis. and Engin. Chem., 4 (1912), No. 3, pp. 206-209). — 

 Believing that perhaps the reason for high-protein flours containing relatively 

 more gluten than flours which are low in protein was due to a larger content 

 of impurities, the author made tests with gluten from flours representing 

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