BULLETIN OF THE BUSSEY INSTITUTION. ot 
mannan in the wood was hydrolyzed in these experiments, or 
that it is ever in our power to convert the mannan in any sample 
of wood completely into mannose, for some or even much of it 
will be apt to remain combined with cellulose so firmly as to 
resist inversion, while a part of it will probably be changed to 
‘¢wood dextrin” by the action of the hydrolyzing acid in the 
same way that cellulose is thus changed. Moreover, the precipi- 
tation of the mannose-hydrazone must necessarily be incomplete 
because this substance is by no means totally insoluble in water, 
and because of the risk of the precipitate’s becoming unduly con- 
taminated with dextrose-osazone if it is left to stand too long in 
order that it may accumulate and increase. But it is to be 
observed that the results here recorded are comparable one with 
the other, since the trials were made under similar conditions, 
though it would probably have been better, as I can now see, to 
have evaporated the products of the hydrolyses before adding 
the reagent. 
For the analysis of the pine seeds 27 grm. were taken and 
treated in a slightly different way from the foregoing, in that the 
material was not subjected to the preliminary leachings with water, 
alcohol, and dilute soda lye which had been applied to the pine 
wood. The powdered seeds were simply boiled at once with the 
hydrochloric acid of 5 per cent., and the hydrolysis was repeated 
thrice as before. No precipitate of mannose-hydrazone was 
obtained on testing the neutralized product of the third hydrolysis, 
and since the liquors from the first and second hydrolyses mani- 
festly contained but little if any of it, they were evaporated on a 
water-bath to rather less than half their original bulk. After 
filtering off a certain amount of gelatinous matter that formed on 
neutralizing the acid liquors, the two solutions were treated, 
together, with the phenylhydrazin acetate, but no precipitate of 
mannose-hydrazone could be detected. 
In brief, it appeared as the result of the quantitative experi- 
ments, made in the manner and under the conditions above 
described, that | 
3.61 per cent. of mannose was obtained from the wood (regarded as 
dried at 100° C.) of the pine tree felled in August, and 
1.86 per cent. of mannose from the wood of the pine tree felled in 
December, while no mannose was got from the pine seeds. 
