ECONOMIC BIOLOGY 3^3 



thread with which the leaves have been stitched together. The ink used 

 in printing was made of carbon which came from burning wood, and the 

 glue and paste used in making the cardboard covers and attaching the bind- 

 ing to the leaves were probably manufactured from gums or juices of 

 plants, perhaps even from the stalks of maize. And even if the adhesives 

 were wholly or partly animal glue, they would not have been possible 

 without plants which provided food for the features whose hoofs, horns, 

 and hides supplied the glue. 



Until one gives serious thought to the matter and looks about at the 

 innumerable things upon which we depend, one does not realize the extent 

 to which we employ plants to supply both the necessities and luxuries of 

 life. It is not even necessary to trace back various substances and materials 

 to their original plant sources, or to argue that by doing so all animal life is 

 dependent upon plants. So let us confine ourselves to materials obtained 

 directly from plants. 



Among the most important and valuable plants of commerce and indus- 

 try are those which supply us with fibers. Moreover, there is a vast number 

 of these fiber-producing plants, some of which are very familiar to every 

 one and serve us everywhere every day. Others are strange to most per- 

 sons, even though their fibers are commonly used, while others are seldom 

 used except by the natives of the lands where they occur. Yet some of these 

 little known fiber-plants are superior to many of our own and deserve to 

 be much more widely used than they are. 



Probably the most famihar of all plant fibers is linen which is made 

 from the leaf and stem fibers of the flax plant, and cotton from the seed- 

 coverings of the cotton plant. Next in importance in our everyday life 

 are hemp, iManilla, jute, and sisal. An entire volume might be written about 

 these alone, and a very romantic and interesting story it would be, for 

 these four fibers come from widely separated parts of the world and are 

 grown and gathered by strange races amid strange surroundings. 



Hemp is obtained from the heinp pla?it which is a native of India and its 

 vicinit}^ Manila or Manila hemp, which is the source of the best cordage 

 and ropes, especially for use on shipboard, is obtained from a very diff'er- 

 ent plant, a variety of the banajia which is a native of the Philippines and the 

 East Indies. Jute is another Oriental fiber derived from an East Indian an- 

 nual plant with tall stalks and yellow flowers. Although one of the most 

 important and valuable of fibers it is not very strong and hence is not suita- 

 ble for high-grade cordage. But it is fine, silky, easily woven and serves a 

 multitude of purposes. Great quantities are used in making gunny sacks or 

 burlap bags. Immense amounts in the form of "tow" are employed for 

 caulking the seams of vessels, for making coarse and cheap papers, for fiber 

 carpets, rugs, seat-covers, curtains, draperies, and "art" fabrics, while the 

 finer grades are used in place of hair on wigs for actors. 



Sisal comes mainly from Mexico, Central and South America, the West 



