CHAPTER III.
Section Cutting.
Embedding of sections.—Before sections are made the tissues require to be embedded in some fluid, which will permeate their interstices, and is capable of being rendered firm so as to support the most delicate parts when the knife passes through the tissue.
The most generally useful substances are:—
(1) gum, (2) celloidin, (3) paraffin or wax.
Gum.—Picked colourless gum arabic 2 parts, cold water 3 parts.
Leave with frequent stirring until dissolved. Add ten drops of carbolic acid to each ounce of the mucilage.
Specimens are thoroughly freed from all trace of the hardening fluid by washing in water, and the tissue is then placed in the gum solution for at least twelve hours, or if enough carbolic acid be added, it may be left there for an indefinite time.