Fe! a ' THE MICROSCOPE. 59 
MICROSCOPY.* 
A Limprp Copar Soturion.t—A limpid and colorless solution of 
gum copal has long been a desideratum to microscopists. The follow- 
- ing process is taken by James from the German journal, Der Techniker. 
The latter says that if a high grade of bright copal is chosen, the 
product will be perfectly limpid and almost colorless. By sorting the 
copal, asolution as limpid as water may be obtained : Dissolve 4 parts 
of camphor in 48 parts of sulphuric ether, and add 16 parts of pulver- 
ized gum copal thereto. Cork the flask carefully, and stand aside 
with occasional agitations until the copal is partly dissolved and 
partly swollen to its fullest extent. Then add 16 parts of alcohol of 
96 percent. and 1 part rectified oil of turpentine, and agitate thor- 
oughly. Let stand with occasional agitations for several days, and at . 
the expiration of a week or so, the contents of the flask will be found 
to have separated into two layers, of which the lower is rather dark, 
thick, and possibly dirty, according to the quality of the copal, but 
above this a layer will be found rich in copal and as clear as crystal 
itself. The lower layer may be further treated with camphor and ~ 
sulphuric ether, and afterwards with alcohol, and made to givea 
still further yield of the crystalline fluid. The only objection to this 
solution of copal is that it is somewhat brittle when dry. This may 
be obviated by adding a few drops of purified nut or poppy oil 
thereto. 
Moprrication or WieGcerT’s Meruop ror STarnine Fisrin in SEc- 
rrons.—{The method, which is described in detail in the Fortschritte 
der Medicin, vol. xviii., p. 693, 1888, is as follows: The sections 
are spread out on glass slides, dried with filter paper, stained for 
five minutes in gentian anilin water, and again dried with filter 
paper. They are then placed in Lugol’s solution of iodine for from 
thirty to sixty seconds, and finally decolorized in a mixture of xylol 
one part, and anilin oil two parts. They are mounted in balsam. 
The specimens should be hardened in alcohol. By this method the 
shreds of fibrin are stained a deep blue, all the other parts being 
decolorized. They show much better in the daytime than by artifi- 
cial light. . 
* Under this heading will be included descriptions of New Instruments, Microscopical 
manipulations, Stains and Re-agents, Photomicrography, ete. 
+St. Louis Medical and Surgical Journal, October, 1888. 
+ Medical Review, November 10, 1888. 
