BULLETIN OF THE BUSSEY INSTITUTION. 387 
in wood at different seasons may, perhaps, depend upon other 
motives than the necessity of feeding buds and leaves in the 
spring. ‘The analyses go to show, furthermore, that the pento- 
sans in the wood of trees can hardly be regarded as of the 
nature of reserve food, though it must be admitted that we are 
still profoundly ignorant as to the chemical behaviour of these 
substances within the tree. 
Percentage of Pentosans found in the Wood of the Gray Birch 
(Betula populifolia of Aiton). 
Segments of wood were sawed out from the stems of the trees 
at a height about twenty feet from the surface of the ground, 
where the stems were a little more than three inches in diameter, 
and where eighteen annual rings could be counted. After the 
bark, both outer and inner, had been peeled and shaved off, the 
blocks of wood were divided into an outer and an inner portion 
by drawing a circle seven-eights of:an inch in radius from the 
centre of the stem and chipping off the wood outside this circle 
with a chisel. The samples of ‘‘ outer” and ‘‘ inner” wood thus 
obtained, were chipped into small pegs which were dried, ground 
in a mill and powdered. ‘The outer bark was thrown away, but 
the inner bark was examined as stated in the text. 
To estimate pentosans,* weighed portions of wood were dis- 
tilled with hydrochloric acid of sp. gr. 1.06, the distillate was 
mixed and stirred with phenylhydrazin acetate, the precipitate was 
collected on an asbestos filter, then dissolved in alcohol, as sug- 
gested by Krug, and dried thoroughly at about 60° C. The weight 
of the precipitate multiplied by 0.516, gives the theoretical weight 
of the furfurol, and to this weight'has been added the conven- 
tional correction 0.0104, to compensate for matter dissolved from 
the precipitate during the process of washing, and for incomplete 
subsidence of the precipitate also. 
Percentage of Furfurol obtained from the Wood of Gray Birch 
Trees felled at Different Seasons. 
From the tree There was obtained per cent of furfurol (wood dry at 100° C.) from the 
felled in Inner Wood. Outer Wood. Bark. 
6 SR 21.32 19.62 16.75 
Siete . (1.) 16.55 
18.84 11.45 
a (II.) 16.62 ; 
aia 5 cp 3's 16.21 16.29 12.32 
* See Wiley’s Principles and Practice of Agricultural Analysis. Easton, 
1897. 3. 179, 183, 587. 
