750 HISTOLOGIC TECHNIC 



4. Dehydrate quickly in 95 per cent, and absolute alcohol, kept at 

 or near C. 



5. Embed in paraffin. At a convenient time, cut and mount. 

 The stain is rather unstable, but may be kept fairly well if mounted 



in glycerin or in neutral balsam. 



This technic is invaluable for the demonstration of the terminal 

 nerve supply of tissues. 



Methylene Blue, for chromophilic (tigroid) granules in cyton and 

 dendron (Nissl's Method): 



I. Stain: 



Methylene blue (Griibler's 'B pat/) 3.75 grm. 



Venetian soap (white Castile) 1.75 grm. 



Distilled water 1000 c.c. 



II. Differentiating Solution: 



Anilin oil (pure) 10 c.c. 



95 per cent, alcohol 90 c.c. 



This method is only applicable to tissue which has been fixed in 95 

 per cent., or in absolute alcohol. Thionin may be substituted for the 

 methylene blue in the stain. 



1. Warm the stain till steam begins to rise ; then immerse the 

 sections for four to six minutes. They acquire a deep blue color. 



2. Rinse in distilled water. 



3. Differentiate in the anilin alcohol till the sections become a light 

 blue, carefully observing each section (twenty to sixty seconds). 



4. Wash in 95 per cent, alcohol. 



5. Clear in equal parts of origanum and cajuput oils, and mount 

 in neutral balsam or in colophonium dissolved in xylol. 



Cajal's Method for Demonstrating Neurofibrils: 



1. Fix small pieces of tissue in 10 per cent, formalin for six hours. 



2. Wash in water for four hours. 



3. Transfer to 40 per cent, alcohol for six hours. 



4. Place in 50 c.c. of 40 per cent, alcohol, adding 5 drops of am- 

 monia, for twenty-four hours. 



5. Transfer to 1.5 per cent, silver nitrate solution at incubator tem- 

 perature (38 C.) for five days. 



6. Rinse, and place in a solution of 1 gram pyrogallic acid or hydro- 

 chinon, 100 c.c. water, and 15 c.c. formalin for twenty-four hours. 



7. Pass through graded alcohols, and embed in paraffin or celloidin. 



