Micro-chemical reaction.—Both blue and yellow with iodine solution.
In examining a paper containing esparto under the microscope, the pulp will be found to contain, in addition to the fibres of the fibro-vascular bundles, a certain number of the cuticular cells (see Fig. 12), together with some of the fine hairs which are seen in the section (Fig. 10). These are very characteristic.
General chemical characteristics.—Pecto-cellulose mixed with some ligno-cellulose. {57}
Composition (Hugo Müller):—
| Spanish. | African. | |
|---|---|---|
| Cellulose | 48·25 | 45·80 |
| Fat and wax | 2·07 | 2·62 |
| Aqueous extract | 10·19 | 9·81 |
| Pectous substances, &c. | 26·39 | 29·30 |
| Water | 9·38 | 8·80 |
| Ash | 3·72 | 3·67 |
STRAW.
Microscopic features.—Generally similar to those of esparto. There are, however, differences of shape and dimensions of the serrated cuticular cells, which differentiate the various kinds of straw from each other and from esparto.
FIG. 12.
In Fig. 12 are shown these cells, from maize-straw (a and b); from rye-straw (c) and from esparto (d). The {58} following table gives the dimensions of the cells from different kinds of straw:—