18 BULLETIN 309^ U. S. DEPARTMENT OF AGEICULTUKE. 



CELLULOSE FROM ZACATON. 



The sample sent for examination was bleached pulp of Epicampes 

 macroura in the form of waterleaf sheets. The purpose of the work 

 upon it was to determine the nature of its cellulose as completely as 

 possible. 



First, qualitative tests were tried, (a) Fuchsin-sulphurous acid (Schiff' s reagent)' 

 turned a bit of the pulp pink on standing a few minutes. (&) Sachsse's solution (alka- 

 line Hgl2,2KI) was reduced on boiling with the pulp, (c) Fehling's solution was 

 reduced on boiling with the pulp, (d) Vitz's methylene-blue test (boiling a bit of 

 the pulp for 15 minutes with 0.5 per cent aqueous solution of methylene blue) dyed 

 the pulp deep blue, which was not removed by long washing. A bit of pure rag paper 

 was put in the dye at the same time, as a check. It dyed light blue and washed nearly 

 white under the same conditions of treatment, (e) Phenylhydrazin acetate boiled 

 with the pulp gave a yellow hydrazone. (/) Ferric ferricyanid (Cross and Bevan) 

 gave a blue precipitate with the pulp on standing some minutes. According to Cross 

 and Bevan, this reaction is a quantitative measure of lignin. Later work has shown, 

 however, that oxycellulose gives the same precipitate, (g) On distilling from a sus- 

 pension of the pulp in hydrochloric acid of 1.06 specific gravity and adding a phloro.- 

 glucin solution to the distillate, a large amount of furfural phloroglucid was precipi- 

 tated. These reactions show conclusively that the sample contained oxycellulose in 

 considerable quantity. 



As oxycellulose is quite sensitive to attack by many destructive agencies, it was 

 of importance to determine how much was in this sample from Epicampes macroura 

 in relation to other celluloses. In the present state of knowledge (which, unfortu- 

 nately, is rather a state of ignorance) of the constitution of cellulose, it is impossible 

 to say how much of any given sample is oxycellulose. However, it is easy to compare 

 samples and determine which has more or less of it. 



Accordingly, comparative quantitative determinations were made of (1) copper 

 number and (2) furfural yield on the cellulose from Epicampes macroura, a bleached 

 soda poplar pulp, and on cotton "cellulose" simultaneously. The "copper number" 

 of Schwalbe is the number of grams of copper precipitated by boiling 100 grams of 

 the pulp in question for 15 minutes with Fehling's solution, under certain definite 

 conditions of concentration, heating, and so on. In the absence of other reducing 

 substances it is an admirable measure of oxycellulose; hence, it was used here with a 

 modified Low volumetric method of determining the copper instead of Schwalbe'& 

 slower and no more accurate electrolytic method. 



It is at once evident that the Epicampes cellulose contains slightly more oxycellulose- 

 than the poplar pulp and much more than the cotton. (Contrary to the commonly 

 accepted belief, the writers have found most cotton cellulose to contain a little oxy- 

 cellulose, as shown by many tests.) 



For further confirmation and comparison, simultaneous quantitative estimations of 

 the furfural yield from the same cotton, poplar pulp, and Epicampes pulp were made, 

 following the method of Flint and Tollens. This, of course, would not be applicable 

 in the presence of wood gums or various other pentosans or furfurosans, but was here 

 applicable because the other furfural-yielding groups were absent. 



The numerical results of these two analyses are shown in Table III. 



