Feb. 24,1923 
Distribution of Pentosans in the Corn Plant 
659 
METHYL, pentosans 
The various parts of the corn plant were analyzed for methyl pentosans. 
The method of Ellett and Tollens (5) was used in which the precipitate 
of phloroglucid is extracted with 95 per cent alcohol at 6o° C. until 
extraction is complete. Results identical with those reported in an 
earlier paper were obtained. In three determinations of total pentosans 
the decrease in the weight of the phloroglucid (about 0.200 gm.) varied 
from 0.0006 to 0.006 gm., the average being 0.0037 gm. These deter¬ 
minations were made on 1 gm. of dried material and therefore indicate 
the presence of only about 0.37 per cent of methyl pentosans in the 
tissue of the com plant. 
Because of the general distribution of methyl pentosans in plant 
tissue which has been reported by other investigations it was deemed 
desirable to check our procedure by a determination on rhamnose. 
Table II .—Conversion of rhamnose into methyl phloroglucid under various conditions, 
and solubility of the phloroglucid 
Sample. 
Weight. 
Yield of 
phloroglu¬ 
cid accord¬ 
ing to 
Krobers 
tables. 
Phloroglucid obtained. 
Phloroglu¬ 
cid ex¬ 
tracted by 
alcohol. 
Rhamnose. 
Gm. 
r 0.1 
. Gm. 
0. 0587 
. 1364 
. 0860 
Gm. 
O. 0425 
Per cent. 
72.4 
76.3 
93-3 
Gm. 
O. 0425 
Arabinose. 
l -2 
. I 
. 1041 
. 0802 
. IO41 
.0050 
Rhamnose. 
. I 
.0587 
• 1770 
Arabinose. 
. 2 
Total. 
•2357 
. 2184 
92. 6 
• 0358 
Plant material. 
I. O 
. 1672 
.0587 
. 0860 
Rhamnose. 
. I 
Arabinose. 
. I 
Total.. 
• 3“9 
.2958 
94.8 
. 0386 
Plant material. 
I. O 
. 1672 
.0587 
Rhamnose. 
. I 
Total. 
.2259 
. 2084 
92. 2 
. 0482 
