1883. ] Microscopy. 109I 
fluid consists of a concentrated solution of celloidin in a mixture 
of equal parts of absolute alcohol and ether. The specimen is 
soaked successively in absolute alcohol and ether, and in the im- 
bedding fluid. This requires at least several days. After this 
time the imbedding proper may be undertaken, and for this we 
have the choice of two methods. 
The even surface of a cork is covered with a thick solution o 
celloidin, so as to form, by evaporation, a strong collodion mem- 
decker gives for imbedding in paper boxes. As other observers 
have remarked, his method frequently gives rise to a great num- 
eq 
moistened with a drop of ether. This moist surface is adapt 
E the stratum of liquid celloidin on the cork, and exposed for a 
di Minutes to the open air. After this the whole 1s placed in 
ilute alcohol, which in a few hours will unite the imbedding- 
mass solidly with the cork. 
