300 PROCEEDINGS OF SOCIETIES. 
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 whichhairs 
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 wit- 
nessing its appearance during dissolution. A careful examination 
of cotton in the copper solvent, with powers varying from 50 to 
1200 diameters, showed me the appearances described by Mr. 
O'Neill. I could not, however endorse his interpretations of 
them. On the 16th of January, 1865, I sent a letter to the 
chairman of the microscopical section, stating my belief that the 
spiral appearances ‘could be clearly traced to a mechanical action 
which the solvent exerted on the vegetable cell, and that at some 
future time I hoped to illustrate this to the members of the 
section. Since December last I have subjected cotton during 
microscopical examination to a variety of influences in acids, 
alkalies, metallic solutions, iodine, and also gun-cotton in varied 
proportions of ether and alcohol. Repeated experiments tend to 
confirm my disbelief in the existence of spiral vessels, properly 
so called, either inside or outside cotton hairs. It would be diff- 
cult to explain, by means of drawings, how these pseudo-spirals 
are created, and I have, therefore, supplied a number of micro- 
scopes for the purpose of showing, at the close of the meeting, the 
actual appearances. Some of the gentlemen present have wit- 
nessed these experiments, but, for the benefit of those who have 
not, I shall attempt a brief explanation to enable them to com- 
prehend more readily what they will see under the microscopes. 
In order to observe the action of the copper solvent on cotton, 
place a few hairs about a quarter of an inch in length on a glass 
plate, and cover them with thin glass; it is useful to rub a little 
beeswax on the glass plate, in such a manner as will just support 
the covering glass, to prevent too great a pressure on the cotton ; 
then arrange the cotton under the microscope with a power of 
not less than 200 diameters. The solvent should be applied by 
a glass pipette to the edge of the covering glass whilst the 
observer is looking through the microscope (this is important) 
Tf the solvent is very strong the action is too rapid for the eye to 
follow, if of moderate strength it will be seen that as soon as 
the solvent comes into contact with the cotton in the field 
of view a rapid rotation or twisting of the hairs takes place, 
In my opinion it is this rotating action which brings about the 
appearances which have been mistaken for spiral vessels. The 
explanation which I have to offer for the phenomenon is this— 
first, we have the external membrane of the cotton, then the 
cellulose and primordial utricle, and finally, the dried contents in 
the cell, which I take to be the remains of the organizing fluid. 
Observation shows that the external membrane is not elastic, and 
only partially soluble. The cellulose is exceedingly elastic and 
