302 ^ REAGENTS AND PROCESSES 



An excellent double stain with fuchsin and methyl blue is 

 obtained as follows. Leave sections in the above fuchsin 

 solution overnight or for several hours. Wash the sections 

 thoroughly in water and rinse in 95 per cent, alcohol quickly 

 and remove them quickly to water while the stain is still coming 

 off in clouds and transfer them to a saturated solution of methyl 

 blue diluted with an equal bulk of water. Leave the sections in 

 this for a few minutes, then rinse them in water and again in 

 95 per cent, alcohol; transfer them to xylene and mount them in 

 Canada balsam. The time ratios for the two stains will vary 

 with different materials, and the ratios are to be changed as 

 experience teaches. 



Fuchsin, Acid. — Excellent for staining crystalloids. The 

 material containing the crystalloids should be fixed in a concen- 

 trated alcoholic solution of corrosive sublimate. Then the sec- 

 tions should be immersed for twenty-four hours in a 0.2 per cent, 

 solution of acid fuchsin, to which a little camphor has been added. 

 To demonstrate crystalloids in plastids the sections should be 

 treated as follows: The sections are placed in a solution of 20 

 per cent, acid fuchsin in 100 gm. of aniline-water. This solution 

 is heated somewhat while the sections remain in it from two to 

 five minutes; they are then rinsed in a solution of i part of a 

 concenrated solution of picric acid in alcohol and 2 parts of water. 

 This solution should be warmed to about 40° C, and the sections 

 should be rinsed in it until they cease giving off color to it. 

 Thereafter they are dehydrated in strong alcohol, passed into 

 xylene, and mounted in Canada balsam. 



Acid fuchsin is an excellent stain for leucoplasts and plas- 

 tids in general. The material is fixed in a concentrated alco- 

 holic solution of corrosive sublimate in absolute alcohol, where 

 the material remains for twenty-four hours; then the fixative 

 is washed out in alcohol containing iodine. Sections from this 

 material are placed in a 0.2 per cent, solution of acid fuchsin in 

 distilled water. After remaining twenty-four hours they are 

 taken out, washed in running water for a time, and then are 

 examined in glycerine or are allowed to dry, after which they 



