428 Vegetable Fibres Available for 
ment of fibres. But, from the very facility of their action 
on matter closely allied to cellulin, it will at once be per- 
ceived that their effect on cellulin, must be powerful :—ex- 
perience shows that it sustains a considerable loss of 
strength. A large number of experiments have clearly 
proved that the exposure of cellulin to the smallest quan- 
tity of alkali capable of solving other vegetable substances 
in any perceptible degree, will cause a loss of strength 
which is of very considerable importance in the bleaching 
of yarns and of fabrics; and in preparing pulp for paper 
from rags, fibres, and wood. Nor is the action so minute 
as to be merely an infinitesimal fact magnified into a bug- 
bear. The cell loses its sustaining power, even when con- 
sidered fairly good, from its normal strength of 1:0, until in 
some cases, it reaches 0:4; or, that four cells with their pris- 
tine strength, will sustain the weight of ten of many samples 
impaired by such treatment. Probably, few samples will 
reach 06, which would be considered extraordinary. Again, 
examine this action on the lustrous coat of the cell. To a 
certain extent, the brilliance is due to the state of aggrega- 
tion of the surface, in like manner as the hair-side of leather 
is more compact and smooth, than the flesh-side. This 
surface would not be much altered in appearance by the 
action of any agent upon it. But nature rarely leaves any 
of her surfaces without protection. Above this, is de- 
posited a coat, doubtless as a protection from hurtful in- 
fluences, and to increase elasticity. This coat is suited to 
its position and use. On downs as cotton, we find a secre- 
tion of an oily fluid, designed to shoot off wet, as from a 
duck’s wing. On all fibres, even if embedded in other 
matter, the coat is distinct alike from the cell as from the 
surrounding matter. Its predominating component in some, 
is insoluble albumen; in others, silica; or these substances 
united with bases. If we suppose it simple insoluble albu- 
men, the action of alkalis and alkaline earths, must be 
gradually to remove it. Some fibres prove this supposition 
in a remarkable degree. China grass for example, will 
diminish in thickness of cell to a degree perceptible to the 
naked eye. It has been suggested, that this altered ap- 
pearance is due tothe admitted power of contraction which 
alkalis exercise upon vegetable cells. But Mr. Mercer did 
not, by any means, prove that hot alkaline solutions of long 
‘continuous action, have any such effect, but rather the con- 
trary. It seems also probable, that the effect, where pro- 
duced, is a contraction in length of cell, which, being exer- 
