METHODS OF ANALYSIS. 9 



For weight of phloroglucid (a) from 0.03 gram to 0.300 gram Krober's i:ill-" is 

 recommended. If this is not. available use the following formulas: 



Furfural =(a+0.0052)X0.5185 



Pentoses =(a+0.0052)X 1.0075 



Pentosans = (a+0.0052) X 0.8866 

 For weights of phloroglucid (a) over 0.300 gram. 



Furfural = (a+0.0052) X 0.5180 



Pentoses =(a+0.0052)X 1.0026 



Pentosans=(a-f 0.0052) X0.8824 



DETERMINATION OF REDUCING SUGARS AND SUCROSE. 



\Yeigh 13.2 grams into a 200 cc flask, add about 150 cc water, and shake occasionally 

 for one hour. Add 5 cc alumina cream and make up to 200 cc with water, shake, 

 and filter off 100 cc into a 110 cc flask. Make up to the 110 cc mark with lead sub- 

 acetate, shake, and filter through a folded filter into a small Erlenmeyer flask. If the 

 solution is cloudy return to filter, until a clear filtrate is obtained. This is solution "A." 



REDUCING SUGARS AS DEXTROSE. 



To 25 cc of solution A add exactly 5 cc of concentrated sodium carbonate solution. 

 Shake and filter through a 9 cm filter into a small flask. Return to filter until a clear 

 filtrate is obtained. Use 20 cc for the determination of dextrose according to Allihn's 

 table (20 cc equals 1 gram of original substance). 



SUCROSE. 



Transfer 50 cc of solution A to a 55 cc flask and make up to the 55 cc mark with 

 concentrated hydrochloric acid. Mix well and heat in the water bath with bulb of 

 thermometer as near to center of flask as possible until it registers 68 C., taking 15 

 minutes in the heating. Transfer the solution to a small beaker and neutralize with 

 sodium carbonate. Transfer to a 100 cc flask and make to mark with water. Filter off 

 25 cc for the determination of total reducing sugars (25 cc equals 0.75 gram of the 

 original substance). Before calculating the invert sugar obtained as sucrose from a 

 lulile for invert sugar, deduct the reducing sugars, determined as invert sugar from 

 the same table. 



The results were first figured on the basis of the sample as received 

 at the laboratory. The sum of the percentages of the different con- 

 stituents determined does not equal 100 per cent, but the results are 

 as close as can be expected, with the present methods. Factors used 

 for calculation are often of an arbitrary nature, as in the cases of pro- 

 tein and pentosans, and results can not be considered as absolute. 

 Also a number of substances, such as galactan, are not determined. 

 All of the results were refigured to a moisture-free basis. 



METHODS OF MANUFACTURE OF STOCK FOODS. 



On account of the numerous and varied sources from which the 

 so-called concentrated feed stuffs are derived, it is essential to know 

 something of the raw materials entering into these products and the 



a Journal fur Landwirtschaft, 48, 1900, p. 379; U. S. Dept. Agr., Bureau of Chcini.-- 

 try, Bui. 107, page 226. 



