SECTION FOUR 



METHYL VIOLET - EOSIN SCARLET 

 A botanical stain for mitosis in root tips 



Solutions required: 



A. Methyl Violet 5B aqueous 1%. 



B. Picric acid 1% in absolute alcohol. 



C. Eosin scarlet, saturated in equal 



volumes of clove oil and absolute 

 alcohol. 



Technique: 



1. Sections are fixed to slides and taken down to water in the 

 usual manner. 



2. Stain for twenty to thirty minutes in the methyl violet solu- 

 tion ; then wash with distilled water. 



3. Differentiate with the picric acid solution for a few seconds. 



4. Immerse in absolute alcohol to which has been added 0-15% 

 strong ammonia solution, for fifteen to twenty seconds. 



5. Immerse in absolute alcohol for ten to twenty seconds. 



6. Counterstain for five to fifteen seconds in the eosin scarlet 

 solution. 



7. Clear in clove oil ; rinse with xylol ; mount. 



Results: 



Resting and dividing chromatin, purple. Cytoplasm, pink. 

 Cell walls, red. Plastin, deep red. 



NIGROSINE 

 For the study of salivary chromosomes of Drosphila 



Solutions required: 



A. Acetic acid 45% aqueous 



B. Absolute alcohol . . . . . . 70 ml. 



Distilled water . . . . . . 29 ml. 



Hydrochloric acid, pure, cone. . . i ml. 



307 



