406 
add one part of glacial acetic acid to twenty parts of 
stock. Fix until the tissue is opaque throughout (one 
or more hours). Wash in water till washings colourless 
and free from acid (an hour more or less). Preserve 
in eighty per cent, alcohol. This is an excellent 
general fixative. 
N.B.—The sublimate is best removed from the sections before 
staining by Lugol’s solution. 
8. LugoVs Solution .— 
Iodine - - - - - 1 *o gr. 
Potassium iodide - 2'o gr. 
Water ----- ioo*o 
Treatment and Preservation of Fixed Tissues 
1. The best method, if possible, is after washing 
out the fixative to imbed the tissue at once or after 
some daps in paraffin (p. 46). Pour the paraffin out 
into paper boats, small match boxes, etc. The tissues 
will then keep indefinitely. 
2. The next best method is after washing and 
dehydrating to pass into cedar wood oil and preserve 
in the oil. 
3. If neither of these methods is possible, then 
after washing (and passing through increasing strengths 
of alcohol, if required) to preserve in rectified spirit, 
or eighty-five per cent, alcohol or methylated spirit. 
The staining of tissues is somewhat imperfect after 
long preservation in alcohol. 
Washing the Fixed Tissues 
If the fixative used has been an alcoholic one, then 
wash out in absolute alcohol (or spirit). (This, as will 
be seen, saves a good deal of subsequent trouble.) 
If the fixative has been a watery one, then it is 
