6 
Indian Forest Records. 
[VOL. Ill 
whole length of the culm. It is this facility of separation of its fibrous 
structure and absence of interlacing with adjoining filaments, together 
with the large interior surface of the pores exposed to chemical action, 
(provided the air is expelled), which permits us to remove it from the 
category of impervious hard woods in which its high sp. gr., and trans¬ 
verse hardness would otherwise place it. It has therefore little mass 
resistance to the action of solvents. 
7. The pectous and ligneous constituents of bamboo will be dealt 
with fully in section B, but their colloidal resistance to the penetration of 
liquor is of a physical nature and finds a place in this section. Pectose 
is of a gelatinous nature, lignin being more like resin, and, like glue and 
resin, the first effect of solvent action is, with both, to produce a partially 
dissolved water-proof colloidal film which protects the tissues it encloses 
from the further action of the solvent. The influences which overcome 
this resistance are strong liquors, high temperatures and prolonged 
duration of digestion, each being, within certain limits, complementary to 
the others and capable of being substituted for each other. Ligno-cellu- 
loses, such as spruce, contain much lignin but no pectose, while pecto- 
celluloses, such as the smaller fibrous grasses, have a large quantity of 
pectose and little or no lignin. Bamboo contains both in considerable 
amount, and its resistance from this cause alone is equal to that of spruce, 
while its total resistance from mass, colloids and capillary air is greater 
than spruce. 
8. Nodes are a prominent feature in all Graminece but in the annual 
grasses and cereal straws they are so small and slightly lignified as to give 
little trouble to the pulp-maker. In bamboo they are large, hard and 
strongly lignified, and have hitherto been found so difficult to digest 
that no good results were possible unless they were cut out and 
rejected. This means not only a considerable loss of raw material but 
much expenditure on cutting apparatus, the hard siliceous cuticle being 
very destructive of steel cutting edges. Contrary to what might be 
expected, the nodes are not denser than the internodes. On the contrary 
their sp. gr. is less, so the difficulty found in their digestion is not due to 
greater density; they contain, however, larger proportions of both pec¬ 
tose and lignin, the treatment of which gives rise to some difficulty. It 
is not merely the additional quantity of NaOH required to resolve them, 
since digestions with NaOH in large excess of the amount required fail 
to give good results, but the greater and more persistent colloidal resis¬ 
tance exercised by the larger and thicker masses of pectous and ligneous 
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