APPENDIX II 695 
The acetic acid in all of the Flemming fluids is of great 
advantage since it penetrates very rapidly, carrying the chromic 
acid or chromic and osmic acids into the tissue depths, thus 
insuring complete fixation. : 
The material to be fixed should be cut into small pieces not 
longer than 5 mm. nor broader than 20r 3mm. The amount of 
fixative to be used should not be less than 15 times the bulk of the 
material to be fixed. For delicate material, the weak fixing fluid 
is used, while for the slightly woody the medium strength fluid 
and for the more woody, the strong fluid is indicated. The 
material should be placed in the fixing fluid immediately after it 
is gathered. One or two drachm homepathic phials are con- 
venient for the process. The material is kept in the fixing fluid 
for from 12 to 24 hours and then washed in small cheese cloth 
bags which are placed in running tap water for from 6 to 12 
hours or over night. 
DeHYDRATING AND HARDENING OF SOFTER PLANT MATERIALS. 
After washing, the material, still kept in the bags, is placed in 10 
per cent. alcohol for 1 hour and is then carried through a series of 
alcohols. Each of the series 10 per cent. stronger than the one 
before it, remaining in each grade for 11% to 2 hours until 70 
per cent. alcohol is reached. Take out of bag and place in phial 
in 70 per cent. alcohol. If the material is not to be imbedded in 
paraffine immediately, it can remain in 70 per cent. or 85 per 
cent. alcohol (if very delicate) until needed. It is not safe to 
leave very valuable material in a grade below 70 per cent. over 
night. From the 70 per cent. alcohol it is carried to 85 per cent. 
to 95 per cent. to absolute alcohol, remaining in each at least 6 
hours with 2 or 3 changes of the last. 
CLEARING AND IMBEDDING OF SOFTER PLANT MATeErIALs.—In 
order to get the material from absolute alcohol into paraffine, 
some medium must be used which mixes with absolute alcohol 
and which also dissolves paraffine. Either oils such as cedar, 
clove or bergamot or substances like xylol, chloroform or benzol 
satisfy this requirement. To clear with xylol—transfer material 
from absolute alcohol to a mixture of 34 absolute alcohol and 14 
xylol for 12 hours, then to mixture of equal parts of absolute 
alcohol and xylol for 12 hours, then to 34 xylol and 14 absolute 
