eee oe en 
APPENDIX II 697 
are simplified while hardening and shrinking in many materials 
are avoided. 
DeEHYDRATION.—For small cubes of woody material, keep one 
hour in each of the following solutions (over night in No. 6): 
ee ee OS oe ee Se I 
Water's cir r Celta Wee to ee eS 25 ARS 
95% :B. Ale, ) Hoo. eo ers B40; 20: 30: 35:50: 45... 40. 25 
Abs. butyl (03.3), 2 tgsgae 7 ee eee a 208 989) 90, 7 ot LOO 100 
Water oe 90 8 75 65 45 25 15 15 5 
95% EB. Ale. / Acai ede 5 10 20 30 50 70 80 50 40 
Abe. 8, Ales i; a ee ees sly is AS re sae Oi RP Sancza 
Abs. Butyl... .i35 6 re Re aS 80, 18 On 
Material should remain in pure butyl alcohol until all water is 
removed. ‘This usually requires several hours. 
INFILTRATION.—Pour paraffin into vial (one-half or two-thirds 
full) and allow to cool. Place material in butyl alcohol on top 
of paraffin and put vial into oven. After material has stood in 
the melted mixture for an hour or so, pour off mixture and add 
pure melted paraffin. Repeat after another hour. ‘Two or more 
such changes are necessary, depending on the size and nature of 
the pieces of material. All the butyl alcohol should be removed 
before imbedding, although traces of it do not interfere with 
sectioning as do similar amounts of xylol. 
TECHNIQUE OF SECTIONING AND MountInG MATERIAL 
IMBEDDED IN PARAFFINE 
Strip off the paper tray from the imbedded material and cut 
out a block of paraffine containing the object which is to be 
sectioned, taking care to include at least 2 or 3 mm. of paraffine 
on all sides beyond the specimen. ‘Take a segment of pine wood 
about an inch long and with a surface at one end about 3 in. 
square, and coat the square area with melted paraffine. Warm 
the paraffine on the piece of pine wood and quickly press the 
paraffine block containing the specimen into this melted paraffine 
in the desired position for cutting. Heat a dissecting needle and 
apply this all around the base so that the paraffine block is 
firmly sealed to the wood. Dip paraffine block in cold water to 
