Method I 19 



decolorization by dipping the slide through 70 per cent, alcohol 

 until the sections become pink with just a shade of blue, about 

 30 seconds. 



14. To dehydrate, transfer to 95 percent, alcohol for 20-30 

 seconds and thence to absolute alcohol for 5-10 minutes. 



15. To clear, transfer from absolute alcohol to xylol for 

 15-20 minutes. 



16. To mount, remove the slide from xylol, lay it flat, place 

 a small drop of balsam or colophonium (F ) on the sections, and 

 put on the cover-glass, 



To avoid air bubbles, begin at one edge of the cover and 

 gradually let the cover down. Handle covers with fine flat- 

 pointed forceps. 



Do not allow the xylol to evaporate sufBciently for the sec- 

 tions to become dry before covering. 



The reticulum of the cell is stained pink, the granulation blue, 

 the neurosomes black-blue. The axone hillock is distinguished 

 by being devoid of the larger granules. In the developing ner- 

 vous system, cells in the process of karyokinesis stain more 

 deeply blue than do the others. 



An oil immersion lens is necessary to study the finer detail 

 of the cell structure. 



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