CLEARING AGENTS

Stieda relates that kreasote was suggested him by a paper of
Kutschin, "17ber den Bau des Riickenmarks des Neunanges,"
I Kasan, 1863. Kutschin rinsed his sections in water, brought
them on to slides, drew off the water by means of blotting-
paper, and added a drop of kreasote at the side. When
clear, he covered, and closed the mounts with a border of
dammar.
Stieda modified this process by mounting in dammar instead
of kreasote.
He then tried experiments to ascertain whether oil of
cloves could be applied in the same manner, that is, to the
clearing of non-dehydrated sections. He found that it could,
though   its employment requires longer time.        Sections
brought from water into kreasote clear in a few minutes,
whilst in oil of cloves they require from half an hour to an
hour or more; and this slowness of the process exposes them
to the risk of shrinkage.
Further experiments with other essential oils led him to
establish the following classification:
A. The turpentine group, capable of clearing in a short
time perfectly dehydrated sections, but clearing watery
sections only after many hours or not at all.
01. Terebinthine.
01. Absynthii.
01. Balsam. Copaiv.e.
01. Cortic. Aurantiorum.
01. Cubebarum.
01. Feeniculi.
01. Millefolii f1orum.
01. Sassafras.
01. Juniperi.
01. Menthae cripsoe.
01. Origani vulgaris.
01. Lavandule.
01. Cumini.

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