38 Neurological Technique 



During the period of fixation the tissue should be kept in the 

 dark. 



2. To wash. — Remove the now blackened pieces of nerve 

 from the cardboard, with scissors clip off the bent and ragged 

 ends, and wash in several changes of distilled water for 4-12 

 hours. 



3. To harden, replace the water with 70 per cent, alcohol for 

 15-20 minutes, and then replace 70 per cent, with 95 per cent. 

 alcohol for 12-24 hours. 



4. Stain intoto. — Replace 95 per cent, with 70 per cent, alcohol 

 for ID minutes, and then transfer to 10-15 ^^- o^ the aqueous 

 fuchsin solution (B) for 12-24 hours. 



5. Wash in 70 per cent, alcohol for 10-15 minutes. 



6. To complete the washing and to dehydrate, transfer the 

 pieces of nerve to 20-30 volumes of absolute alcohol and let 

 remain for 2 or 3 days. 



7. Clear and imbed in paraffin as quickly as possible (for detail 

 see I, 3 and 4, p. 16) . 



(«) Clear in about 20 volumes of fresh xylol for 20-25 

 minutes. 



((5) Transfer to melted soft paraffin for about 15 minutes. 



(f) Melted hard paraffin for 20-30 minutes. 



(d) Imbed and cool as directed in I, 4, (<;) and (d), p. 16. 

 The proper orientation is of great importance, since the appear- 

 ances obtained depend much upon the plane at which the speci- 

 mens are cut. Place the pieces of nerve in the paper box of 

 melted hard paraffin, laying same across and at right angles to 

 others, so that both transverse and longitudinal sections may be 

 obtained at the same stroke of the knife. 



8. Make sections about 6 micra or less. (See I, 5, p. 17.) 



9. Fasten sections to the slide by the water method (I, 6, 

 p. 17). 



10. When dry, dissolve off the paraffin by immersing the 

 slide in xylol for 10-15 minutes. Then lay the slide level, put 

 a small drop of balsam on the sections, and put on the cover- 

 glass (I, 16, p. 19). 



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