APPENDIX 245 



washed out from everything except the nuclei ; they are then at once trans- 

 ferred to turpentine, and from this are mounted in Canada balsam. 



10. Aniline blue-black. Dissolve 1 gramme of aniline blue-black in a 

 mixture of 30 parts of water with 20 of alcohol. This serves for staining the 

 central nervous system either in bulk or in sections. 



11. Staining with chloride of gold. a. Cohnheim's method. Place the 

 fresh tissue for from 30 to 60 minutes in per cent, solution of chloride of 

 gold ; then wash and transfer to a large quantity of water just acidulated 

 with acetic acid. Keep for 2 or 3 days in the light in a warm place. 



3. LowiVs method. Place small pieces of the fresh tissue in a mixture 

 of 1 part of formic acid to 2 to 4 parts of water for i to 1 minute ; then in 

 1 per cent, chloride of gold solution for 10 to 15 minutes ; then back again into 

 the formic acid mixture for 24 hours and then into pure formic acid for 24 

 hours more. After removal from the gold, and whilst in the acid, the tissue 

 must be kept in the dark. 



y. Ranvier's method. Immerse in lemon-juice for 5 to 10 minutes, then 

 wash with water and place in 1 per cent, gold chloride solution for 20 minutes. 

 Then treat either as in Cohnheim's or in Lowit's method. 



12. Staining with nitrate of silver. Wash the fresh tissue with distilled 

 water; immerse in to 1 per cent, nitrate of silver solution for 5 to 10 

 minutes ; rinse with distilled water and expose to bright sunlight either in 

 water, alcohol, or glycerine. 



Mounting Solutions : 1. Saline solution. A 0'6 per cent, solution of 

 common salt is used in place of serum f6*r mounting fresh tissues for imme- 

 diate examination. 



v 2. A mixture of glycerine and water in equal parts. 



3. Farr ant's solution. Take a mixture of equal parts of glycerine and 

 saturated watery solution of arsenious acid, and stir gum arabic with it until a 

 thick syrupy fluid is formed. Filter. 



4. Canada balsam, from which the volatile oils have been driven off by 

 heat, dissolved in benzole. 



