PROCEEDINGS OF SOCIETIES. 301 
soluble, and expands to a remarkable degree in the act of disso- 
lution. The contents of the cell behave in a similar manner to 
that of the external membrane; it is neither elastic nor very 
soluble. The most successful experiment is made by allowing 
the copper solvent to come at once into contact with some length 
of the cotton hair. The solvent permeates some parts of the 
external membrane more easily than others, and causes a rapid 
expansion of the cellulose, which bursts the external membrane, 
and as this action is taking place at various portions of the same 
hair, a tangential force is exerted which twists and contorts the 
cotton in the direction of its length, and thus a spiral appear- 
ance is given to the whole structure of the cell. The non- 
elastic external covering is twisted round the expanded cel- 
lulose, sometimes as a single band, at others like a bundle of 
fibres. In those parts where the external covering has given 
way all round the hair the cellulose expands into a bulb, 
pushing back the external membrane into a series of folds, 
which form a ligature, and resists the expansive force of 
the cellulose. A number of these ligatures cause the ex- 
panded cellulose to assume the appearance of a string of 
beads. The lateral expansion of the cellulose contracts the 
length of the hair, and this causes the contents in the cavity of 
the cell to assume a corrugated appearance ; this corrugation has 
also been subjected to the twisting power along with the other 
parts of the cell, and thus its spiral appearance is produced. 
‘What becomes of the primordial utricle I cannot state with cer- 
tainty. After the disappearance of the cellulose there is an 
envelope left, which surrounds the contents of the cavity ; this 
may be the primordial utricle, or the film left by the drying up 
of the protoplasmic or organizing fluid. If the solvent is made 
to come into contact with the ends of recently cut cotton, a beau- 
tiful trumpet-mouth is produced—the exposed surface of cellu- 
lose has expanded and pushed back the external coverings into 
folds—the contents of the cell may, in this case, be seen pro- 
jecting from the mouth of the trumpet form. Long after the 
complete dissolution of the cellulose has taken place the external 
membrane remains just as the rotations or twistings had left it, 
some portions in the form of rings, which had been the ligatures 
between the bulbous expansions, other portions as irregular 
spirals. The cell contents also remain as twisted corrugations. 
From the observed difference in solubility between the cellulose 
and the external and internal matter, I should imagine a differ- 
ence in constitution. A few experiments have led me to suspect 
that some of the spiral appearances observed in hemp and flax 
fibres during dissolution may possibly be caused by the mecha- 
nical action of the solvent employed. 
P.S.—In making the cupric oxide with ammonia, the oxide of 
copper requires a thorough washing before dissolving in the am- 
monia. ‘The presence of any salt of ammonia, even in ve 
small quantities, interferes with its power in dissolving cotton. 
