1884.] Microscopy and Histology. 843 
is prepared in plates, and may be obtained from Wittich & Ben- 
kendorf, Chaussee Strasse 19, Berlin N. 
Schiefferdecker uses two solutions, one of a syrupy consistency, 
the other somewhat thinner. The celloidine plate is cut into 
small pieces and dissolved in absolute alcohol and ether (in equal 
parts). Objects are transferred from absolute alcohol,’ first to the 
thinner solution, then to the thicker. After remaining a few 
hours (or days, according to the character of the object) in the 
latter they are imbedded in paper boxes. As soon as a hardened 
Im forms on the solution in the box, the whole is placed in 82 
per cent alcohol for 24-48 hours, and thus rendered sufficiently 
hard for cutting. 
Blochmann recommends imbedding on a cork rather than in a 
paper box, as less celloidine is required, and as the cork is held 
more firmly in the holder. One end of the cork is made rough 
and surrounded by a strip of paper, which is made fast by a pin, 
as shown in the figure. The roughened surface of the cork is 
wet with absolute alcohol and then the object im- 
bedded in the usual manner. In order that this 
sthall box may sink in alcohol, in which it is placed 
for hardening. the celloidine, it may be weighted 
with a small lead ball fastened to the cork by a nee- 
dle (see figure). 
In cutting, the knife is kept wet with alcohol (70 
per cent). The sections may be placed in water or 
in alcohol, and afterwards stained with carmine or 
hematoxylin, in which the celloidine is only a little 
or not at all, stained. Aniline dyes color the cel- 
loidine, and therefore should not be used. 
he sections can be mounted in glycerine or in | 
m; but in the latter case they must be anhy- 
drated with 95 per cent alcohol, as absolute alcohol dissolves ‘the 
celloidine. They should be clarified in bergamot oil or origanum 
oil (clove oil dissolves the celloidine). 
_ Objects imbedded in celloidine can be preserved, ready for cut- 
ting, for a long time in 70-80 per cent alcohol. 
Imbedding in Paraffine —The object is transferred from abso- 
lute alcohol to chloroform, and left till the alcohol has been en- 
tirely replaced ; it is next placed in a shallow vessel with a small 
* 
quantity of chloroform, and enough paraffine added, in fine 
and the chloroform evaporates, so that the object is brought very 
gradually into pure melted paraffine. In this way the object be- 
comes completely saturated with the paraffine. 
l ‘If the objects are penetrated with difficulty, they may be transferred from abso- 
ute alcohol to ether, then to the celloidine solutions. 
