ON MOUNTING INSECTS IN BALSAM WITHOUT PRESSURE. 105 
or tracing amid the simple forms of organic life some of those 
minute structures and marvellous functions which enable us to 
some extent to comprehend our own, we are led to realize a sense 
of the perfection and grandeur of the operations of nature; but of 
the true character of those operations how little we know, and how 
much must ever lie beyond the power of the human mind to 
discover ! 
ON MOUNTING INSECTS IN BALSAM 
WITHOUT PRESSURE. 
By HERBERT CHADWICK. 
EW objects are more beautiful, or more instructive when properly 
mounted, than Insects. For many years it was customary to 
mount such specimens under pressure, a practice which in nearly 
all cases resulted in the destruction of the natural relation of the 
various parts; but of late years, the beautiful preparations sent out 
by Mr. Enoch and others, seem to have awakened microscopists 
to the desirability of mounting their specimens without pressure. 
Having made a series of experiments with this object in view, I 
have written the following notes on the methods employed, hoping 
that they may be useful to those who are engaged in the study of 
the anatomy of Insects. 
PREPARATION I.—Soak the specimens in liquor potasse, until 
they are transparent. Wash well in distilled water, using a pipette 
and camel hair pencil. ‘Transfer to 50 pce. spirit, then to a small 
quantity of pure spirit, in a watch glass or soaking bottle, and 
allow them to stand for some hours. Then add oil of cloves, and 
allow the spirit to evaporate. By this method, the formation of air 
bubbles in the interior of the specimens may generally be avoided. 
II.—Wash well in distilled water. Soak in pure spirit or alcohol 
for some days. ‘Transfer to carbolic acid, until sufficiently trans- 
parent. Then transfer to oil of cloves, but many mounters do 
not consider this necessary. This method should be used in all 
cases where the integument is not too opaque to allow light to 
pass through it before treatment; and it is especially ‘useful in the 
study of the muscles. 
Mountinc.—Take a clean 3 x1 slip, having a sunk cell in its 
centre. Just inside the edge of the cell, equidistant from each 
other, cement three white glass beads a a a with hardened bal- 
sam. Put a small quantity of soft balsam in the centre of the 
cell, and gently warm it over a spirit lamp. ‘Take the object, a 
