30 THE CHEMISTRY OF CATTLE FEEDING 



and they enter largely into the composition of fruits, bulbous 

 roots, e.g. turnips, etc. It may be mentioned in passing that 

 the so-called fibre of these roots is more readily digestible by 

 animals than the fibre of most other plants. 



Jute also is a combination and of much more complex 

 character than flax. The elementary composition is not 

 exactly the same as that of cotton,' but corresponds to the 

 empirical formula C 12 H 18 O 9 or 2C 6 H 10 O 5 H 2 O. Jute, like 

 flax, behaves as a homogeneous product. It is dissolved by 

 zinc chloride solution, and by the ammonia cupric oxide 

 reagent, and can be reprecipitated as a whole. 



It is extremely resistant to the action of hydrolytic agents, 

 but by drastic methods it can be split up into a cellulose and 

 a non-cellulose portion. The true cellulose portion is not 

 identical with cotton cellulose. It is not homogeneous, but 

 consists of two kinds, one of which is less resistant to hydro- 

 lysis and to oxidation than the other. The lignone or non- 

 cellulose portion is also heterogeneous. It contains a furfural 

 yielding complex probably an oxycellulose and another 

 group, or groups, described as keto-ring-hexenes. 



Celluloses of a similar character are of common occurrence 

 in stems and in all woody structures. They form a natural 

 sub-group called ligno-celluloses, of which jute may be regarded 

 as a type. 



The cellulose of grasses and cereal straws consist largely 

 of ligno-cellulose, but they differ from the typical compound 

 in the following important particulars. They are structurally 

 more complex, contain a smaller proportion of true cellulose, 

 and the non-cellulose portion is relatively more susceptible 

 to hydrolysis. 



Lignification is regarded as a process of continuous 

 modification in which the lignone gradually increases at the 

 expense of the true cellulose, probably as a result of oxidation 

 and dehydration. The woods, i.e. timber, represent the 

 extreme limit of this process. The typical ligno-cellulose 

 (jute) in the first year of growth contains from 7.0 to 80 per 

 cent, of true cellulose, whereas the woods contain only from 

 50 to 60 per cent. The woods, however, are regarded as true 



