APPENDIX. 375 



The proportions of borax and carmine given here are 

 not very important; less carmine and more borax 

 may be used. The fluid may be used without the 

 addition of alcohol, or glycerine may also be added 

 to it ; further the precipitate from the alcohol may 

 also be dissolved in water and used. 



Borax carmine is principally used when it is desired 

 to stain nuclei deeply; the staining is usually im- 

 proved by placing the sections for a few minutes in 

 a mixture of 2 parts alcohol and 1 part hydrochloric 

 acid 1 p. c. 



Spiller's purple and Methylene blue. 



These are used in a strong aqueous solution so that in 

 a minute or two the sections are sufficiently stained, 

 they are then washed with water, and mounted in 

 water ; if the staining is too deep, the sections are 

 placed for a short time in alcohol ; the sections 

 cannot be mounted satisfactorily in glycerine,. since 

 the glycerine dissolves the colouring matter and 

 renders the staining diffuse. To preserve the sec- 

 tions permanently they should be over-stained, then 

 passed rapidly through 30, 50 and 70 p. c. alcohol ; 

 they should then be washed with strong spirit 

 (which dissolves the colouring matter very rapidly) 

 until nearly the proper tint is obtained, transferred 

 to absolute alcohol, and in a minute or two to cedar 

 wood oil ; when they have become transparent, they 

 are mounted in Canada balsam. Cedar wood oil 

 instead of clove oil is used to clear the sections, since 

 it does not dissolve the colouring . matter ; Water 



