153 
in length and direction — having a shrivelled appearance some- 
thing like the hark of an aged tree. In gun cotton, the 
transverse cracks are very numerous. From an examination 
of transverse sections of cotton, I incline to the opinion that 
there is an external membrane distinct from the true cell 
wall or cellulose matter ;* inside the cellulose there is an 
irregular cavity, this, in some specimens (when viewed 
longitudinally), appears to contain granules, probably the 
remains of the organising fluid contents of the cell, the 
mucous matter which is seen in growing cotton as mentioned 
by Captain Mitchell, in his letter to Mr. Hurst, read at this 
society, March 22nd, 1864. 
On the 21st of April, 1863, Mr. Chas. O'Neill made a 
communication to this section, “ On the Appearance of 
Cotton Fibre during Solution and Disintegration these 
experiments referred to the application of Schweizer’s solu- 
tion of copper and ammonia. 
Under the action of this solvent, Mr. O’Neill considers 
that cotton exhibits spiral vessels situated either inside or 
outside the external membrane. In a paper, read by the 
same gentleman, on the 18th of May, 1863, it is stated that 
spiral vessels are seen during the solution of gun cotton in 
ether and alcohol. On the 21st of December, 1863, Mr. Heys 
read a paper before this section, in which he refers to spiral 
vessels in cotton hairs which seem to prevent the collapse of 
the tubes. The announcement of the discovery of spiral 
vessels excited my curiosity. Having often examined 
varieties of cotton under the microscope, without suspecting 
any such structure, I was naturally desirous of witnessing its 
appearance during dissolution. 
A careful examination of cotton in the copper solvent, 
with powers varying from 50 to 1,200 diameters, showed me 
the appearances described by Mr. O’JNeill. I could not, how- 
ever, endorse his interpretations of them. On the 16th 
* See Mr. O’Neill’s Paper, April 25th, 1863. 
