THE MICROTOMIST'S VADE-MECUM

placed on a piece of pith to which they will adhere on being Objet
put into the alcohol.)   The alcohol immediately causes the     Okeet
collodion to solidify, without contraction, into an elastic mass  wlole
which supports every part of the contained structures. Sec- lours
tions may then either be cut at once, or the objects may         ill
be left in the alcohol till wanted for any length of time         gP
without further change.                                         tisOna
The sections are cut with a knife wetted with 36' alcohol     4(1A
and are floated into water or on to the slide.
If the object was not previously stained en masse, the        obin
sections may now be stained by carmine or picro-carmine in caj
the usual way.     There is no need to remove the imbedding-
mass, as it does not take the stain.
They may be mounted simply in glycerin; the collodion         str4
will remain as clear as glass. Duval found that he could not     I the
mount them in balsam or dammar as these substances made          arto
the collodion " opaque and     granular."  (I am   unable to    ith
understand this, as I have long mounted mine in balsam or prior
dammar, and found them remain perfectly transparent. Duval      AsI
does not state what clearing agent he employed for dis-          r1
alcoholisation.)  He obtained, however, satisfactory results     Ian16
by dehydrating rapidly with absolute alcohol (absolute alcohol refre
dissolves collodion in a short time, and a delicate section OBl
would thus be deprived of the support necessary to hold its      ukEs
parts together), adding (on the slide) a drop of oil of cloves,  Il
(which entirely dissolves the collodion) and closing the mount   $hti
with chloroform-balsam.                                          shit
256. Collodion-Imbedding (the Author's method).-Hav-           tasit
ing for many months employed the collodion method with           'tgi
most satisfactory results, I shall probably do well to relate     ot
here the details of any practice. I dehydrate my objects        sdi
with alcohol, soak them   in ether, put them into a porcelain    atti
mould, and cover them     with collodion.   I then cover the     spen
mould with a shade, and leave it for a few hours. As soon        8hatil
as the collodion  (of which only just enough to cover the        2rah

194


F-