214 PROCEEDINGS OF SOCIETIES. 
matters by the strong solvent. If the strong solution is first ap- 
plied, the extraordinary diiation of the cellulose bursts the external 
membrane, and reduces it to such a state of tenuity that it is in- 
visible. This membrane is very elastic, appears to be quite imper- 
meable to the solvent, and when free from fissures protects the 
enclosed matter from its action. It is not seen in cotton which has 
been submitted to the action of alkaline acids and bleaching powder, 
being either chemically altered, or, what is most probable, entirely 
removed. 
The spiral vessels are unmistakeably apparent, running round 
the fibre in more or less close spirals, sometimes single, sometimes 
double and parallel, and at other times double and in opposite 
directions, or again seemingly wound close and tight round the 
cylinder. ‘They are well seen in the spherical swellings or beads, 
but are prominent at the points of strangulations of long ovals 
formed when the ends of the fibres are held tightly. They collect 
in a close mass, forming a ligature, and are frequently ruptured, 
the ends projecting from the side of the fibre. 
The cellulose is enormously dilated by the weaker solvent, and 
expands the external membrane into beautiful beads, which are 
doubtless the result of the spiral vessels acting as ligatures at the 
points of strangulation; at the open end of a fibre it can be seen 
oozing out as a mucilaginous substance. The stronger solution 
bursts the beads, or dissolves all the cellulose into a homogeneous 
mass, amidst which the empty cuticular membrane and the spiral 
vessels remain nearly unacted upon. 
The substance called medullary matter is seen occupying the 
axes of the fibres; it is nearly insoluble in the solvents. It may 
be well seen projecting from the open end of a fibre where the 
cellulose is exuding, and often remains im situ when the fibre has 
quite disappeared. It has many appearances of being a distinct 
body, but the author in some cases thought it might be only the 
thickened or modified inner cell-wall; in others it looked like a 
shrunk membrane, probably the dried-up primordial utricle. It is 
generally absent or indistinct in old cotton, or cotton which has 
been submitted to bleaching agents. 
Mr. O'Neill intends to submit further details when his investiga- 
tions are more advanced. 
Mr. Hepworth stated that he had observed spiral markings in 
Sea Island cotton, not subjected to chemical action, and that he 
had calculated there would be about 50,000 spirals to an inch of 
fibre. 
A PAPER 
On the Srructure of the Vatve of the DIATOMACEX. 
By Cuarves Sropper. 
From ‘ Proceed. Boston Soc. Nat. IIist.,’ vol. ix, p. 2, 1862. 
There are recorded a few observations which mention the exist- 
