Experimental and Applied 283 



exposing in closed chambers to an atmosphere of chlorine gas, 

 afterwards removing the chlorinated product by again boiling 

 in alkali. This process is the laboratory method of isolating 

 cellulose applied on the large scale. In the form of cellulose, 

 however, jute comes into unfavourable competition with the 

 woods, and the process is therefore not much used. 



The adipocelluloses come into consideration in this connec- 

 tion, merely as adventitious tissue-constituents. They are a 

 source of considerable difficulty on account of their resistance 

 to the attack of reagents. They occur, of course, chiefly in such 

 raw materials as are entire stems or leaves, e.g. esparto and 

 straw, and are characterised by admixture with chlorophyll 

 (esparto) and oil-wax constituents. For the removal of the latter 

 the alkaline treatment is relied upon, the conditions of which 

 for the purpose require to be much more severe than for the 

 non-cellulose of the fibre-constituents proper. The cuticular 

 cells themselves are only slightly attacked by the process, and 

 are obtained in the pulp, in which they are easily recognised 

 under the microscope by their very characteristic form. The 

 neutral waxes are obtained at the end of the boiling process in 

 mechanical mixture with the mass of pulp and liquor, and they 

 collect on the surface of the lixiviating vats used in the continu- 

 ous process of washing esparto pulp. The treatment of such 

 raw materials, in which all the compound celluloses are repre- 

 sented, is perhaps the best illustration of what has been expressed 

 by an ' overhead ' treatment. The ordinary processes are, in 

 fact, a crude aggregate effect, and it is more than probable that 

 means may yet be devised for more specific treatments, in 

 harmony with the broad principle of economic chemical work. 

 In all these industrial processes for isolating cellulose, moreover, 

 the yield is considerably less than what may be considered the 

 theoretical, i.e. the proportion isolated by the method of chlori- 

 nation (p. 95). For these raw materials which have been more 



