398 PLANTS AND MAN 



or made unfit for drinking by the addition of wood alcohol or 

 other poisonous substances. Pure ethyl alcohol is also used in 

 medicine and surgery. 



When starch is treated with nitric acid, it reacts to produce 

 a substance known as nitrostarch, a high explosive which is 

 much safer to handle than the nitrocellulose discussed later. At 

 the end of the first World War, almost two million pounds of 

 nitrostarch per month was being used in the manufacture of 

 hand grenades. 



Cellulose Products 



From the time man first began to use plant fibers until a 

 scant fifty years ago, the extracted fibers were regarded as the 

 final product of the process and were used for manufacture into 

 textiles and paper in the form provided by the plant. Today 

 these fibers are regarded as the raw materials from which man 

 may build other fibers, almost to his own specifications. This 

 amazing change of outlook may well revolutionize the entire 

 textile industry as well as the cotton growing and forest growing 

 industries, since it is primarily from cotton and wood fiber 

 that the cellulose is derived, to undergo chemical changes 

 from which it emerges as any one of a variety of cellulose 

 derivatives. 



The first step in the manufacture of artificial fibers is the 

 conversion of the cellulose into a liquid form. Then it is forced 

 through tiny "spinnerets" in thin streams and hardened by air 

 or chemicals into new fibers which are twisted together and spun 

 into thread for textile manufacture. There are at least four dif- 

 ferent processes in use for the manufacture of these artificial 

 fibers, which are known as rayons. The most important rayon 

 process, known as the viscose process, consists of treating purified 

 cellulose with caustic soda and then carbon bisulphide. This 

 compound, with the addition of water, becomes viscose which 

 is aged and then forced through the spinnerets into a chemical 

 solution which hardens it into fibers. Cuprammonium rayon is 

 produced by chemical coagulation of cellulose dissolved in 

 ammoniacal copper hydroxide, a strong alkali solution. Celanese, 



