Owing to the fact that a considerable proportion of the pulp obtained from straw consists of cellular tissue (see Fig. 13, p. 58), which, although cellulose, is devoid of fibrous structure, paper made from straw only is found to be much weaker than that made from fibres such as esparto. On the other hand, being a cheap material, and one capable of yielding a very white pulp with a moderate quantity of bleach, it is held in considerable repute by many paper-makers, especially as a material for mixing with esparto. It is sometimes mixed with cotton and linen rags, even in the finest qualities of paper. _Jute, Manilla, Adansonia, &c._—The boiling processes already described under Esparto and Straw are, with certain slight modifications, equally applicable to fibres of this class. For convenience in manipulation they are usually cut into small pieces by a machine such as is shown in Fig. 16, and are then cleaned and dusted in a willowing machine. The boiling process calls for no special notice beyond what has been already said with regard to other fibres. A cheaper method, and one which is largely adopted in mills where only a coarse dark-coloured paper is required, consists in boiling the jute or other fibre in lime. Such a treatment is, however, not so effective as one in which caustic soda is used, and the fibre produced is harder and coarser in every way. The yield of pulp, however, owing to the fact that the fibre is imperfectly resolved, is greater. In many cases, from questions of economy, lime may be advantageously employed. Jute can only be employed successfully when it is imperfectly resolved, that is to say, when it is not reduced to the state of pure cellulose. In such a state it forms a comparatively weak fibre, owing to the fact that it is resolved into its individual fibres. If the filaments are not completely resolved, then a strong fibre is the result, but in this case, the pulp cannot be obtained in a pure white state. Owing to this fact, jute has had up to the present only a limited consumption, except for the manufacture of coarse papers. {104} Jute and Adansonia are largely used for papers where strength is of more importance than appearance, such, for example, as paper for telegram forms, strong wrapping paper, &c. _Wood._—The processes for treating wood have already been described in Chapter V. When an alkaline treatment is adopted, the alkali employed is, at least in this country, caustic soda. In Germany the sulphide of sodium processes have been very largely adopted. The alkali method is, however, being superseded by the more perfect and more economical method of treatment with sulphurous acid or acid sulphites.