42 Neurological Technique 



3. Expose the teased and covered preparations to the sun- 

 light for aboutj^ hour, or until the "crosses" begin to appear. 



4. The preparations may be made permanent by mounting in 

 glycerine jelly (IV, E) or by sealing down the cover-glass with 

 "gold size" or any of the cements specially prepared for cover- 

 glasses. 



MODIFICATIONS. 



1. If in haste, fairly good demonstrations may be obtained 

 by teasing a small shred of flesh nerve in a few drops of the 

 silver nitrate solution on the slide, and, after 20-30 minutes, 

 replacing the silver solution with glycerine, covering and expos- 

 ing to sunlight as before. 



2. Sections. — Pieces of nerve which have been in the silver 

 nitrate solution 12—24 hours may be dehydrated by passing 

 through the increasing grades of alcohol (50 per cent., 70 per 

 cent., 95 per cent., and absolute), remaining 15-20 minutes in 

 each, then cleared in 10-15 volumes of xylol for 20-30 minutes, 

 and imbedded in paraffin as in V, 7, p. 38. 



Make longitudinal sections about 15 micra thick. Fasten sec- 

 tion to the slide, dissolve off the paraffin with xylol, and mount 

 in balsam as in V, 10, p. 38. 



If by now the reduction of the silver is not complete, expose 

 slides to diffuse sunlight for an hour or so. 



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