APPENDIX II 699 
push the sections into even rows. Then leave the sections to 
dry for several hours or over night. 
METHOD FOR THE STAINING AND MounTING OF MATERIAL IN 
PARAFFINE RIBBONS AFFIXED TO SLIDE 
1. Gently heat the dry slides with paraffine ribbons adhering 
to the fixative, high above the Bunsen flame (with the ribbon side 
up). ; 
2. Place the slide upright in a well of xylol or turpentine. 
The xylol or turpentine will dissolve the melted paraffine in a 
minute or two. 
3. Take the slide out of the well, wipe off the under side and 
allow a stream of 95 per cent. alcohol to run over the upper side 
from a pipette. 
4. Place the slide upright in a well of safranin for from four to 
twenty-four hours. 
5. Take the slide out of the safranin well and extract excess of 
stain with 50 per cent. alcohol. If impossible to extract excess of 
safranin by this procedure, use acid alcohol and remove acid by 
washing with 50 per cent. alcohol. 
6. Place the slide in a well of gentian violet or fast-green for a 
second or more. ‘The time varies for different objects and can 
only be determined by trial. 
7. Rinse slide with 70 per cent. alcohol from pipette. 
8. Pour absolute alcohol over sections, follow with a few 
drops of clove oil, replace clove oil with cedar oil. 
9. Mount in balsam. 
10. Label slide. 
IMBEDDING IN CELLOIDIN 
Whenever material is unsuited for free hand sectioning and 
will not give good results when imbedded in paraffine on account 
of size, hardness, or brittleness, celloidin may be resorted to as an 
imbedding medium. 
The technique employed is similar to that of the paraffine 
method so far as the preliminary fixing, hardening and dehydrat- 
ing are concerned up to and including the 95 per cent. alcohol 
