220 Cellulose 



And indeed in the lignocelluloses themselves pectous sub- 

 stances make their appearance with increasing age. Thus the 

 lower portions of the isolated jute bast jute cuttings or butts 

 when boiled in alkaline solution yield products which cause 

 the solution to gelatinise on cooling ; and the gelatinous product 

 is insoluble in alcohol, distinguishing it, as pectic acid, from the 

 products of hydrolysis of the lignocellulose itself, which are dis- 

 solved, after precipitation, by alcohol. It must be remembered, 

 however, that in the 'jute cuttings ' the adhesion of the bark 

 and cortical parenchyma to the true bast fibre is such that we 

 are dealing with a complex tissue, and the source of the pectic 

 acid may be in the parenchyma of the tissue and not in the 

 bast fibre. On the other hand, we have shown (p. 152) 

 that in the spontaneous decomposition of jute, lying in the 

 damp state, gelatinous acid bodies are formed, indistinguish- 

 able from pectic acid. It would not be difficult, therefore, to 

 account for the pectic constituents of the bast tissue towards 

 the root end, as products of degradation of the lignocellulose 

 itself. 



Reverting, however, to the non-lignified fibres such as China 

 grass, or Ramie (Bohmeria species), and the 'nettle fibres 'gene- 

 rally, hemp, and even raw cotton these all contain pectic bodies 

 associated with the cellulose, which are hydrolysed and dis- 

 solved by treatment with boiling alkalis. But these pecto- 

 celluloses have not been sufficiently investigated as compound 

 celluloses to admit of any useful classification on the basis of 

 particular constitutional variations of their non- cellulose con- 

 stituents. 



The monocotyledonous fibre-aggregates, whether fibro- 

 vascular bundles (Phormium, Aloe fibres, Musa, &c.) or entire 

 plants (Esparto, Bamboo stems, Sugar Cane), are largely made 

 up of pectocelluloses, with a greater or less proportion of ligno- 

 celluloses. But the constitution of these non-cellulose con- 



