REAGENTS. 101 



APPENDIX. 



A. VARIOUS REAGENTS USED IN THE STUDY OP PLANT TISSUES. 



PERMANENT STAINS. 



KLEINENBERG'S HJEMATOXYLIN. Saturate some 70 per cent, 

 alcohol with calcium chloride, let the mixture stand 12 to 24 hours 

 over powdered alum, shaking occasionally ; add 8 parts of 70 per 

 cent, alcohol, filter and then add a saturated solution of haema- 

 toxylin in absolute alcohol until a purple-blue color is pro- 

 duced. Let stand in a corked bottle in sunlight for a month; 

 it is then ready for use. The liquid is to be diluted as required 

 with dilute alum solution. Over-stained sections are brought 

 back to proper degree of staining by washing in acidified 70 per 

 cent, alcohol (4 to 6 drops hydrochloric acid to 100 cc. alcohol). 

 Since acids are incompatible with the stain, it is best to wash 

 the section next in alcohol or water containing a trace of am- 

 monia before making the final mount. 



Hsematoxylin is an excellent nuclear and cellulose stain. It 

 scarcely stains lignified material. Alcoholic sections should 

 first be washed well in water and also thoroughly washed after 

 staining. 



BEALE'S CARMINE. Dissolve 0.6 gram of carmine in 2 cc. of 

 hot ammonia water ; let the solution stand 1 to 2 hours to cool 

 and to allow the excess of ammonia to escape. Then add 60 cc. 

 of distilled water, 60 grams of glycerin and 15 grams of abso- 

 lute alcohol. Allow the mixture to stand for some time and 

 then filter it. Over-stained sections are brought back to proper 

 color by washing in acidified 70 per cent, alcohol, then in alcohol 

 free from acid. Carmine is a protoplasmic and nuclear stain. 



FUCHSIN. Dissolve 0.1 gram of fuchsin in 160 cc. of water, 

 add 1 cc. of absolute alcohol. Keep in a well-closed bottle. 

 Fuchsin stains lignified and corky tissues, but is easily washed 

 out of cellulose walls. 



METHYL-GREEN. Dissolve the dye in water to deep green 

 color. This stains lignified and cutinized tissues more rapidly 

 than cellulose tissue. It also stains protoplasm and the 

 nucleus. 



SAFRANIN. Equal parts by volume of aniline water (water 

 saturated with aniline oil) and concentrated alcoholic solution 

 of safranin. Sections stained and then washed in acidified 70 

 per cent, alcohol have only lignified and cutinized walls colored. 



GENTIAN-VIOLET. Three parts by weight of aniline, 1 part of 

 gentian-violet, 15 parts by weight of alcohol and 100 cc. of 

 water. It stains lignified and cutinized walls. 



