ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 
257 
plislied without shifting the latter perceptibly. The slide can then be 
handled with perfect impunity, no matter how soft the balsam may be, 
and a good deal of the superfluous balsam may be removed if care be 
taken not to displace the clips. The balsam may then, if advisable, be 
hardened under more or less heat ; the top of a hot- water cistern is a 
first-rate drying-ground for the purpose. After about a fortnight in 
such a position, even slides mounted in ordinary balsam will generally 
be found sufficiently hard to be cleaned with perfect safety, but theo- 
retically it is evident that the time taken to harden under the cover is 
the same as the time taken to harden in an open vessel by a layer of 
balsam whose thickness is one-quarter the diameter of the cover-glass. 
When the balsam is fully set the points of the clips will be firmly stuck 
down on the slides, but there is no difficulty in pulling them off ; if 
necessary the wires might be heated, but this is not required. 
Mr. Bryan now makes the clips of brass wire, the length required 
for each being about in. It is advisable to make the clips of different 
sizes, to accommodate the different sizes of cover-glasses, and, properly, 
the distance between the points of the clip should be about seven-tenths 
of the diameter of the covers for which it is made. For use with some 
mounts, it is convenient to bend the points of the clip inwards, while if 
the object be a very thick one the points turned down will be found 
very useful. Where neither of these things is done, the ends may be 
filed off at a suitable angle, so that they hold the edges of the cover 
more firmly. 
Quick Method of Mounting Microscopical Preparations.^ — K. 
Schilbersky, jun., finds that numerous micro-organisms can be per- 
manently preserved by mounting them in an aqueous fluid (water or 
dilute glycerin) or glycerin-jelly, by means of the following simple device. 
The object is (suppose) in water, and lying about the centre of the 
cover-glass. Any excess of water is then to be removed with bibulous 
paper, so that the edges of the cover-glass are quite dry ; or this may be 
effected by evaporation. Before the edges are dried it is advisable to 
pass under the cover-glass a droplet of dilute carbolic acid, to prevent 
the development and settlement of schizomycetes, &c. When the edges 
are dry, the corners of the cover-glass are to be fixed with asphalt so 
thick that it runs with difficulty. Along the margins and corners of 
the cover-glass the asphalt is to be applied by means of a brush or glass 
rod, in such a way that the cover-glass is not moved. When complete, 
the ridge may be covered with Canada balsam. 
If the object is in glycerin or other fluid not a solvent of asphalt, the 
procedure is quite similar, but extra care must be taken with glycerin to 
remove all traces of it outside the edge of the cover-glass, otherwise the 
asphalt will not stick. This is best done with a brush or strip of 
blotting-paper moistened with spirit. Instead of asphalt, balsam may 
be used, but it is not quite so serviceable. 
If the object is to be mounted in glycerin-jelly, the following modi- 
fication is adopted. The object (usually obtained by maceration) is 
placed under a cover-glass in water or glycerin, and the latter is then 
absorbed by means of a pipette or blotting-paper to one-third. The 
* Zeitsclir. f. Wiss, Mikr., vi. (1889) pp. 273-83. 
1890. 
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