BULLETIN OF THE BUSSEY INSTITUTION. 417 
yield of wood-gum was less at high pressures than at low, appa- 
rently because of the destruction of some constituents of the wood 
by the extremely hot, strong alkali. 
In the light of what has been learned hitherto, the point of 
especial interest is the fact observed by Hoffmeister, as just now 
said, that after soaking pine, spruce or fir wood in cold, strong 
hydrochloric acid, an abundance of what appears to be wood-gum 
can be dissolved out from these woods by means of dilute soda lye 
acting at the ordinary temperature; the inference being that the 
strong acid has acted in some way to set free or loosen the xylan 
from its combinations in the wood so that it can now be dissolved 
by the caustic soda. 
There appear to be two reasons wlhiy the remarkable facts here 
stated have received comparatively little attention. First: Numer- 
ous indirect estimations of xylan in coniferous woods have been 
made by distilling the wood with hydrochloric acid for furfurol and 
calculating from this product the corresponding amount of xylan 
which is often found to be large. The results obtained in this 
way have been set down in the text-books in the same category 
with those obtained by the direct precipitation of wood-gum from 
the woods of deciduous trees. Second: Some rather confused 
results of Wieler,* who obtained no inconsiderable quantities of 
mixed wood-gum and albuminoids from pine wood, have been 
accepted as if they contradicted the statements above set forth. 
But it is safe to say that Wieler’s work cannot properly be regarded 
as of the same convincing character as that of Thomsen, Koch, 
Hoffmeister, Tollens, and Tauss. 
D. Not much Wood-Gum is obtainable from the Strawberry. — 
The high degree of interest which attaches to the question, What 
is the function or purpose of the xylan that is found in plants? 
has led many chemists to devote their attention to the estimation 
of this substance in a great variety of vegetable matters. Many 
efforts have been made to determine what particular tissues con- 
tain the largest proportion of pentosans and to discover those 
plants or parts of plants from which the pentoses, and especially 
xylose, can be obtained most readily and most abundantly. One 
noteworthy result of this quest is the observation made by Pro- 
* Die landwirthschaftlichen Versuchs-Stationen. $82, 338. 
