MOUNTING OF SPECIMENS. 
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MOUNTING OF SPECIMENS. 
Microscopic preparations or mounts are of two kinds : 
they may serve a temporary purpose only or they may 
be prepared so as to serve for future study, the latter 
being known as permanent mounts. 
In taking up the study of a specimen it should first 
be mounted in water and examined ; then the water 
may be replaced by a weak aqueous solution of glycerin 
(5 to 10 per cent.) and the specimen examined again. 
After this preliminary examination other agents and 
reagents may be employed. Specimens mounted in glyc- 
erin will keep for several days and even months. Gen- 
erally speaking, the only effect which the glycerin has 
on the tissues or contents is that of swelling them, which 
is obviated, to a greater or less extent, however, if the 
glycerin is washed out when an examination is made. 
In addition to the methods involving the use of glyc- 
erin, there are two ways of making permanent mounts, 
depending upon the employment either of Canada 
balsam or glycerin jelly as the mounting medium. 
The method involving the use of the latter is the sim- 
pler, and leaves the specimen in such a condition that 
a re-examination with reagents can be made if desir- 
able. Glycerin-jelly mounts are made as follows : Speci- 
mens which have been previously treated are trans- 
ferred to glycerin and allowed to remain for several 
hours, the excess of glycerin removed, and the speci- 
men transferred to a warm slide on which a drop of 
glycerin jelly 1 has been placed. The preparation is 
1 Kaiser’s Glycerin Jelly.— Soak 7 grammes of gelatin in 42 
grammes of water for two hours; dissolve 1 gramme of carbolic 
acid in 49 grammes of glycerin; mix the two solutions; heat on 
a water-bath, with occasional stirring for fifteen minutes, and 
finally filter through glass wool. The jelly is warmed slightly to 
liquefy it before using. 
