266 Cellulose 



dried at 100, is added to this mixture. The time and condition of 

 treatment may be varied, and the influence of the variations noted. 

 The product is removed from the acid and at once dropped into 

 a large volume of water. It is then exhaustively washed until 

 entirely free from soluble acid products, dried and weighed. The 

 products may be analysed for nitrogen by the standard methods. 



(8) Ferric Ferricyanide Reaction. The solutions of ferric 

 chloride and ferricyanide are prepared at normal strength, and 

 mixed in equal volumes previously to the experiment. The fibre- 

 substance is weighed and plunged into the red solution and allowed 

 to remain, with occasional stirring. The deposition of the blue 

 cyanide within the fibre-substance should be carefully observed 

 under the microscope, and the gain in weight should be determined 

 under varying conditions of digestion. The blue dyed product 

 may be analysed in various ways to determine Fe and N. 



(9) Dyeing Operations. The fibre may be prepared by a pre- 

 liminary boil in weak alkaline solutions. It should then be dyed 

 up in the ordinary way. with coal-tar colours typical of the various 

 groups. It will be found that the lignocellulose has a very varied 

 dyeing capability, corresponding with the great variety of re- 

 active groups which it contains. A systematic investigation of 

 this question is very much wanted. 



(10) Ultimate Analysis. The elementary analysis of fibre-sub- 

 stance may be carried out by any of the standard combustion 

 methods. In respect to the mineral constituents (ash), these must 

 be determined in the usual way, by completely burning the fibre 

 in a platinum dish, and an allowance made for the carbonic acid 

 retained by the ash. With regard to the moisture, the fibre may 

 be dried at 100-105, and in transferring to the combustion appa- 

 ratus, care must be taken that no absorption of moisture takes place. 



The Woods may be treated in the same way as the lignified 

 fibres, provided they are previously reduced to a state of the finest 

 possible division. For this purpose the well-seasoned wood 

 should be cut into shavings, with a fine plane. As stated in the 

 text, there is much need for a thoroughly systematic examination 

 of the woods comparatively with the typical lignocellulose, and there 

 is also room for investigating those woods which contain colouring 

 matters belonging to the aromatic group. In view of the more 

 complex constitution of the woods, care must be taken, in bringing 



