The extract should be dried, and finely powdered, and then extracted with absolute alcohol for several days.
| Powdered extract of logwood | 2 | grms. | 1 1/2 | drms. |
| Absolute alcohol | 10 | c.c. | 1 | oz. |
Filter and add slowly to
| Benzoate of sodium | 1 | grm. | 36 | grs. |
| Alum | 1 | grm. | 36 | grs. |
| Distilled water | 100 | c.c. | 10 | ozs. |
The strength of the solution will vary with different samples of logwood and must be estimated by trial. This solution is comparatively cheap and is useful for class purposes.
Ehrlich’s hæmatoxyline.—This very useful nuclear stain is made as follows:—
| (a) | Hæmatoxyline | 2 | grms. | 9 | grs. |
| Absolute alcohol | 100 | c.c. | 2 | ozs. | |
| (b) | Glycerine | 100 | c.c. | 2 | ozs. |
| Distilled water | 100 | c.c. | 2 | ozs. | |
| Alum | 120 | grms. | 2 1/2 | ozs. | |
| Glacial acetic acid | 5 | c.c. | 24 | mins. |
Add (a) slowly to (b) with constant agitation.
Allow to ripen in sunlight for two months before using. It may be employed as a rapid stain undiluted but far better results are obtained by using a weak solution, a few drops to a watch-glass full of distilled water, and staining slowly for from half an hour to two hours. The solution improves by keeping. If after a time the staining becomes diffuse it is an indication that the acetic acid has evaporated, and a few drops more should be added.