256 KIYOYASU MARUI 



4. Levaditi preparation (14 series each of normal and fa- 

 tigued brains). 



5. Bielschowsky preparation (6 series each of normal and 

 fatigued brains). 



6. Cajal preparation (5 series each of normal and fatigued 

 brains) . 



Besides these I used the following stains in the present work: 



7. Scharlach stain (5 series each of normal and fatigued brain). 

 The fish brain was fixed in 10 per cent formalin twenty-four 

 hours, rinsed with water, cut at 15/i with the freezing micro- 

 tome. The sections were stained in saturated solution of Schar- 

 lach R in 70 per cent alcohol, rinsed with distilled water, counter- 

 stained with diluted Ehrlich's hematoxylin solution, washed 

 again, and mounted in glycerin. As there is only one pair of 

 Mauthner cells in a fish brain, it was rather hard to get the sec- 

 tions in which the Mauthner cell is found. 



8. Mallory preparation (5 series each of normal and fatigued 

 brain). In this preparation the brain was fixed first in 10 per 

 cent formalin twenty-four hours and then placed in formol-Zenker 

 fluid twenty-four hours. Paj-affin sections 5 to 8m thick were 

 stained with a diluted solution of Mallory 's hematoxylin, 



9. S.-fuchsin-light green stain (5 series each of normal and 

 fatigued brains). Brains were first fixed in 10 per cent formalin 

 twenty-four hours and then placed for eight days in the chromic 

 acid acetic acid mixture. Paraffin sections of bfj. were treated as 

 follows: 1) Remove paraffin from the sections and pass to 96 

 per cent alcohol. 2) Place sections for one hour in a saturated 

 aqueous solution of S-fuchsin in the incubator at 58°C. 3) Wash 

 twice with distilled water, till no more stain comes out of the 

 sections. 4) Dip the slides in motion 10 to 20 seconds in the 

 following solution : 



Saturated alcoholic solution of picric acid 30 

 Aqua destillata 50 



5) Rinse carefully twice in water. 6) Place the slides in a sat- 

 urated aqueous solution of light green twenty minutes. The sec- 

 tions were then washed with water, dehydrated very quickly and 

 passed into xylol. 



