270 INTRODUCTION TO PLANT GEOGRAPHY [CHAP. 



Cellulose is soluble in various solvents such as concentrated nitric 

 acid, and this has led to the development from it of ' plastics ' and 

 unbreakable glasses and many other important products including 

 guncotton, cordite, collodion, celluloid, cellulose acetate, viscoses 

 such as Cellophane, and various varnishes and fabrics including cloth 

 and leather substitutes. Photographic film is made chiefly from 

 cellulose nitrate or acetate coated with gelatin, while further breaking 

 down of cellulose yields various sugars which in turn yield alcohol 

 and, with appropriate treatment, Torula Yeast or other foods. Alto- 

 gether cellulose products are countless in number and of great value 

 and usefulness ; moreover, being formed often from forest waste, 

 they seem endlessly replaceable. 



Clothing Materials and Other Fibres 



Clothes, one of Man's primary requisites, are made largely from 

 plant fibres or materials obtained from animals which are dependent 

 on plants for food. In addition, fibres and fabrics are used by 

 Man in innumerable other ways. Indeed, fibre-yielding plants are 

 probably second only to food plants in their influence on civilization 

 and their general usefulness to Man. But although there are many 

 hundreds of fibre-yielding plants known, only a few are of com- 

 mercial importance. 



From the point of view of their utilization, fibres produced by 

 plants or from plant materials may conveniently be classified into 

 seven groups: (i) Paper-making fibres, which were discussed in 

 the last section dealt with above. (2) Artificial fibres, whose pro- 

 duction is nowadays a great and expanding industry. The main 

 raw materials are {a) cellulose, derived from wood pulp or cotton 

 linters, whence are made the various so-called ' rayons ', and (b) 

 soft coal, whence are produced the various nylons and related 

 materials which between them have now some hundreds of important 

 uses. (3) Textile fibres, used as fabrics, netting, and cordage. 

 These include cotton of various kinds, flax, hemp, jute, ramie, 

 Manila hemp, sisal, coir, and many others. (4) Brush fibres, which 

 are tough and stiff, the chief being the piassavas and their allies, 

 obtained from certain Palms, and Grasses such as Broomcorn, 

 Broomroot, and Spartina. (5) Plaiting and tough-weaving fibres, 

 employed for making straw hats, baskets, chair-seats, matting, 

 wickerwork, etc., for which the stems of various Palms, Grasses, and 

 grass-like Sedges and Rushes are used. (6) Filling fibres, used for 



