76 THE MICROSCOPICAL NEWS. 
CARBOLIC ACID IN MOUNTING. 
By Wi.1aMm J. Pow. 
N our last number there appeared an article on the subject of 
mounting without pressure, taken from an English periodical. 
In that article the advantages of the method described were well 
set forth, and no reader can fail to appreciate the value of any 
process which enables us to remove the air from an object with- 
out drying it, and causing it to become hard, and readily injured 
by handling. The method there described is an excellent one 
when the insect to be mounted is opaque, and of considerable size, 
The use of the soda-solution is to make the opaque portions 
transparent, and it softens the hard parts. 
There are many insects which do not require the use of the 
solution of soda, and even among those that do require it to 
render them quite transparent, may still make beautiful objects 
when mounted in balsam by the method to be described in this 
article. For ourselves, we do not like to use alcohol in mounting 
insects, because it hardens the parts, making them stiff, and not as 
readily arranged as may be desired. In the case of vegetable 
tissues it is sometimes objectionable for the same reason. An 
excellent substitute for alcohol, and one that can be universally 
used in its stead in mounting, is carbolic acid. Contrary to the 
general opinion carbolic acid is not an acid, and the name is 
misleading. It has no acid properties whatever. Chemically 
speaking it is an alcohol, belonging to a series of alcohols quite 
different in composition from common ethyl alcohol, which we 
use, and from wood spirit, which is closely related to common 
alcohol. But carbolic acid is, nevertheless, a true alcohol, and for 
this reason it can be frequently substituted for ethyl alcohol in 
microscopical work. But what advantages has it over the latter? 
One great. advantage is found in the readiness with which it 
penetrates a specimen, and mixes with the fluids used in mount- 
ing, such as water, glycerine, and Canada balsam. Another is, 
that it does not harden tissues and make them stiff. For this 
reason insects, or parts of insects, can be preserved indefinitely in 
carbolic acid, in a fit condition to be mounted at any time. The 
more delicate parts are made quite transparent by long soaking in 
the solution ; but this is no detriment to them. 
It is our custom, when going out in the country, either for a 
walk, or to collect objects for the microscope, to carry a small 
wide-mouthed bottle along, about half full of carbolic acid. Into 
this we immediately drop any minute insects we may find. The 
acid kills them instantly, and in most cases their legs are not 
