HOW TO USE THE MICROSCOPE 29 
thin, flexible part of a plant, it may be placed between pieces 
of elder pith or slices of carrot or potato before cutting. 
SHORT PARAFFIN PROCESS 
In most cases, however, more perfect sections will be ob- 
tained if the specimens are embedded in paraffin, by the quick 
paraffin process, which is easily carried out. 
After boiling the specimen in water, remove the excess of 
moisture from the outer surface with filter paper or wait until 
the water has evaporated. Next make a mould of stiff card- 
board and pour melted paraffin (melting at 50 or 60 degrees) 
into the mould to a height of about one-half inch, when the 
paraffin has solidified. This may be hastened by floating it 
on cool or iced water instead of allowing it to cool at room 
temperature. 
The specimens to be cut are now placed on the paraffin, 
with glue, if necessary, to hold them in position, and melted 
paraffin poured over the specimens until they are covered to a 
depth of about one-fourth of an inch. Cool on iced water, 
trim off the outer paraffin to the desired depth, and the speci- 
men will be in a condition suitable for cutting. 
Good workable sections may be cut from specimens embedded 
by this quick paraffin method. After a little practice the entire 
process can be carried out in less than an hour.: This method 
of preparing specimens for cutting will meet every need of the 
pharmacognosist. 
LONG PARAFFIN PROCESS 
In order to bring out the structure of the protoplast (living 
part of the cell), it will be necessary to begin with the living 
part of the plant and to use the long paraffin method or the 
collodion method. 
Small fragments of a leaf, stem, or root-tip are placed in 
chromic-acid solution, acetic alcohol, picric acid, chromacetic 
acid, alcohol, etc., depending upon the nature of the specimen 
under observation. The object of placing the living specimen 
in such solutions is to kill the protoplast suddenly so that the 
parts of the cell will bear the same relationship to each other 
