308 Transactions of the Society. 
ground glass and water only, to avoid the adherence of particles of 
pumice to the collodion or in surface cavities, which would detract 
from the cleanliness and beauty of the preparation. When sufficiently 
thin, the section may be mounted, surface dry , in stiff Canada balsam, 
or what may he better, the styrax used for mounting diatoms, but the 
mounting should by preference be accomplished without the applica- 
tion of heat, or at most only the slightest increase of temperature, to 
avoid vaporizing the moisture contained in the cavities or tubes of 
the tissue. If the temperature be raised to a greater extent the 
mounting medium runs in, leaving the intimate structure filled with 
the red collodion, a result which may be useful under some circum- 
stances. By this method any unsuspected or abnormal cavities are 
made very evident by the coloured collodion. Brittle tissues are 
made less friable by the toughness of the collodion, and the work of 
grinding down much facilitated. I may here give a useful suggestion 
in reference to the staining of the collodion with the fuchsin : this 
dye should be mixed in the methylated spirit used for making the 
collodion, and the requisite quantity of ether be added and well 
shaken up, then the pyroxiline added. If the alcoholic solution of 
fuchsin is added to the collodion after it is mixed the alcohol in this 
solution precipitates the collodion in a gummy mass, and so toughens 
it that it fails to permeate the tissue, but prepared in the manner I 
have just indicated it preserves its fluidity, and should it by evapora- 
tion become thickened it can be diluted with a little more ether. I 
have tried the other anilin dyes such as Bismarck brown, iodine- 
green, and methyl- violet, but cannot at present get such a satisfactory 
result as I have with fuchsin. 
This method as applied to the osseous and dental tissues is, I 
believe, new, and might be regarded as something almost too simple to 
bring before a body of such accomplished microscopists as form the 
bulk of this Society ; yet the suggestion of it may lead to its employ- 
ment in other directions, and I hope that much benefit may arise to 
its employers from its underlying possibilities. 
