404 BULLETIN OF THE BUSSEY INSTITUTION. 
process of determining cellulose, as proposed by Lange,* which 
consists in fusing with solid caustic potash the wood or other mat- 
ter to be analyzed. As will be seen below, this attractive process 
has proved to be much less efficient than it seemed to promise. It 
has failed signally to effect a complete separation of pentosans 
from the cellulose proper. 
As employed in this laboratory the process of Lange may be de- 
scribed as follows:—Five grm. portions of finely-ground, air-dried 
wood are digested for twenty-four hours, with occasional stirring, in 
soda lye of 5% to remove wood gum, fat, albuminoids, coloring matters, 
etc. The supernatant liquid is syphoned off as completely as possible 
from the undissolved wood, the latter is transferred to a tubulated 
retort, and thirty grm. of solid potassium hydrate-are: put into the retort. 
which is then heated in a paraffine bath, gently at first, but after a time 
the heat is increased very slowly and gradually, though steadily, in 
such wise that at the end of an hour the thermometer in the bath shall 
have risen to 180° C. By proceeding in this way all trouble from 
frothing or bumping is avoided. The retort is maintained at the tem- 
perature of 180° until the mass has become dry, when it will be found 
to all appearance to be thoroughly decomposed. The temperature is. 
allowed to fall to 80°, the cake is dissolved in hot water, an excess of 
dilute sulphuric acid is added, then soda lye to slight alkalinity and the 
cellulose is finally collected on a weighed filter and washed with hot. 
water, alcohol, and ether. 
The purpose of the digestion in soda lye before the fusion is to facili- 
tate the final filtration of the cellulose. Thanks to the removal of dis- 
turbing gummy and slimy matters, the final filtration now becomes. 
not only possible but comparatively speaking easv. This digestion 
with soda lye might, perhaps, be made to serve also incidentally as a 
means of collecting the ‘* wood-gum.” The results given in the follow- 
ing table were obtained by this method, after some mechanical diffi- 
culties, which were encountered at first, had been overcome : — 
Kind of Wood. Per cent of ‘‘ cellulose’? found by Lange’s (KHO)} 
method, (wood dry at 100° C,). 
Outer Wood. Bark. 
Gray Birch felled in October. . .... . . 53.28 i 
Sugar Maple ‘* ‘ cs sh, poweta a ht cee 40.75 
Peach-Stoneps 305.) o\ We 8 Mei el rls! Nee 0 
Apricot ‘ Pie WER Oe OL oe nw es 
Date Cr ta ee Se STR, at 2 is een 
Byory Wut!” SOLS At 8 oak ee ne Seis Ole ee 
hs a en ee ee Re a Re ea Ny 
* Zeitschrift fiir physiologische Chemie. 14, 283, 328. 
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