18 BULLETIN" 983, U. S. DEPARTMENT OF AGRICULTURE. 



which the acid was neutralized before drying show no difference be- 

 tween neutralized and unneutralized material. 



LEACHED TREATED SAWDUST. 



Duplicate 100-gram samples of digested sawdust were weighed 

 into Jena beakers holding 600 c. c, approximately 300 c. c. of water 

 was added, and the beakers were placed on the steam bath. After 

 30 minutes the solution was filtered, and the filtrate was collected in 

 a 2-liter volumetric flask. More water to the amount of 300 c. c. 

 was then added to the sawdust, and the heating was repeated, a 

 longer time being allowed for each extraction. The total time of 

 extraction was 2 days, two of the extractions extending over night. 

 The filtrate was' made up to 2,000 c. c, and the latter was used for 

 analysis. 



SUGARS. 



Allihn's method of determining the reducing sugars, by means of 

 Fehling's solution, as given in Bureau of Chemistry Bulletin 107 

 Revised, was followed. The copper oxide was filtered in an asbestos 

 Gooch crucible, washed with hot distilled water, and dissolved with 

 7 c. c. of concentrated nitric acid. It was then diluted and filtered 

 into a 300 c. c. beaker and electrolyzed after the addition of 5 c. c. of a 

 saturated sodium acetate solution. Hollard's stationary electrodes, 

 consisting of a gauze cathode and a wire-frame anode, were used with 

 a current density of 7.5 amperes at 2.4 volts. After all the copper 

 was deposited, the electrodes were washed in water, alcohol, and 

 ether, dried and weighed, and the dextrose was calculated from the 

 copper numbers in the above-mentioned bulletin. 



TOTAL SOLIDS. 



One hundred cubic centimeters of the extract was evaporated to 

 dryness in a tared crystallizing dish (in a tannin oven or on the 

 steam bath), then placed in the 105° C. oven one hour, and finally 

 cooled in desiccator and weighed. 



VOLATILE ACIDS. 



^ 100 c. c. sample of the extract was distilled to heavy frothing 

 with 10 c. c. of 85 per cent phosphoric acid. Distilled water to the 

 amount of 100 c. c. was then gradually added from a separatory 

 funnel, as fast as distilled, until the volume of distillate approxi- 

 mated 200 c. c. The distillate was then made up to 250 c. c. A 100 

 c. c. sample of this distillate was treated in a covered beaker with 

 about 2 grams of mercuric oxide for three hours on the steam bath. 

 After removal from the steam bath, 10 or 15 c. c. of phosphoric acid 

 was added, and the sample was redistilled. Three titrations were 

 then made, as follows: On the original sample, which gave the total 



