Ii8 
OTIS F. CURTIS 
above the ring would have been very much less; for in such cases shoot 
growth is quickly checked while in the present instance the shoot growth 
was apparently no less than in the check. The sugar content below the 
lower ring was less than that between the rings, showing that from this 
region some of the carbohydrates had been carried backward to the trunk 
whence they were carried towards the roots or to branches higher up. 
The unringed branch showed a sugar content higher than that above the 
ring and lower than that between upper rings, or below the lower ring, as 
would be expected. 
After the removal of the soluble carbohydrates the residue was treated 
according to the Sachs method to determine the starch content. The 
material was boiled for two and one half hours under a reflux condenser 
in a flask with lo percent hydrochloric acid of 1.9 specific gravity. The 
data obtained are recorded in table 13. 
Table 13. Acer saccharum. Polysaccharides from xylem hydrolyzed by Sachs method. 
Extracts made up to 500 cc, 25 cc. of this diluted to 200 cc. and 
$0 cc, samples analyzed 
Dry Weight of 
Xylem 
Mg. of Sugar Ex- 
pressed as Glucose 
Average of 
Determinations 
Mg. of Glucose per 
25 Gms. Dry Wood 
Above upper ring 
Between rings 
23-33 
31-78 
49.88 49.02 
73.00 72.55 
49-45 
72.775 
4,429 
4,580 
The data indicate that there are more polysaccharides present in the 
stem between the rings than above, an equivalent of 151 milligrams of glu- 
cose. It is very evident, however, that by this method of extraction much 
material of the wood that is not starch is hydrolyzed. The iodine test 
showed only very faint traces of starch above the rings, yet by this method it 
would seem that this part of the stem contained starch to the extent of 
about 1 7. 1 percent of the dry weight. It is very probable that pentosanes 
and possibly other polysaccharides were hydrolyzed. 
Table 14. Acer saccharum. Sugars from wood soluble in 95% alcohol. Extract made 
up to 100 cc, 25 cc. samples taken 
Determinations 
Expressed as Mg. of 
Invert Sugar 
Average of 
Determinations 
Total Mg. Soluble Sugar 
Calculated for 25 Gm. 
Dry Matter 
Above upper ring 
12. 1 II. 8 
31-35 31.35 
11-45 
31-35 
45-80 
125.40 
A second set of samples was extracted after a somewhat different manner. 
Pieces of xylem were sawed more finely into sections about one millimeter 
thick. Twenty-five gram samples of this dry material, including the saw- 
dust produced in the process, were placed in 250 cc. of 95 percent alcohol and 
boiled for three hours in a flask with a reflux condenser. The solution was 
filtered off and the residue was extracted in the same way in fresh alcohol 
