COTTON. 91 



undergoes an important change when treated with Schweitzer's solution 

 (an amraoniacal solution of cupric hydrate). 



The late Mr. Chas. 0'.Neil, of Manchester, made some experiments 

 upon cotton fibres under the influence of Schweitzer's solution. Under 

 the microscope, he noticed, first, the outside membrane which did not dis- 

 solve iii the solution ; second, the real cellulose beneath, which dissolved, 

 first swelling out enormously and dilating the outside membrane ; third, 

 spiral fibres or markings apparently situated in or close to the outside 

 membrane (or coating), not readily soluble in the copper solution and 

 not so elastic as the material of the outside membrane, but acting as 

 strictures upon it; these produced bead-like swellings of a most 

 interesting appearance; fourth, an insoluble matter occupying the core 

 of the cotton hair, which very much resembled the shrivelled matter 

 in the interior of quills prepared for making pens. 1 



If the conclusions arrived at by the late Mr. Chas. O'Neil are 

 accurate in every detail, then the structure of the vegetable cell or 

 cotton hair is perhaps more complex than those of living plant cells 

 generally. Mr. John Butterworth, F.R.M.S., 2 of Shaw, Lancashire, 

 also made some investigations upon the cotton fibre, and has shown 

 that spiral markings may be seen very clearly upon them. If cotton 

 fibres are treated with concentrated sulphuric acid they swell up and 

 form a gelatinous mass, and the addition of water causes a precipitate 

 to be formed. This material, which has been called amyloid, forms 

 the basis of vegetable parchment. 



Collodion is obtained from cotton by acting on it with nitric acid. 

 The action of nitric acid upon cotton is variable, depending upon the 

 mode of application. If applied hot, it decomposes the fibres or converts 

 them into oxalic acid ; if applied cold, it may be converted into nitro- 

 cellulose, from which the highly inflammable product pyroxylin or 

 gun-cotton is manufactured. Nitro-cellulose has been used for making 

 artificial silk. 



Acids have so destructive an effect on cotton fibres that their use 

 in the cotton industry ought generally to be dispensed with, since 

 alkalies, such as soap, borax, ammonia, and phosphate of soda, can be 

 employed for scouring and cleaning cotton fibres without materially 

 injuring them. In boiling cotton with caustic alkalies the air ought 

 to be excluded and the goods kept well under the surface of the liquid, 

 otherwise defects will be caused in the bleaching of the go.ods. 



Mercerised Cotton. The fibres of cotton, when immersed in a 

 solution of caustic soda of a density of 45 to 50 Twaddell, undergo 

 an important change. The cell-wall of the multiple fibres that make 

 1 See Marsden's Cotton Spinning. - Now deceased. 



