36 NUCLEAR STAINS. 



The nuclei are differentiated from the ground substance 

 by Alcohol washing. 



A washing in Distilled Water,* previous to the Alcohol, has 

 the effect of fixing the stain in the nuclei so that it is less 

 readily washed out in the Spirit. This is especially the case 

 with Methylene Blue and Methyl Green, which must be washed 

 thoroughly in water previous to being treated with Alcohol. 

 If this be not done the colour will be almost completely 

 removed by the Spirit. Treated in this way, however, the 

 nuclear staining is very fine. 



Vesuvine may or may not be previously washed in Dis- 

 tilled Water, according to the depth of stain required. If 

 water be used the colour is stronger, but less easily removed 

 from the ground tissue. The Yiolets and Safranine are better 

 washed out at once in the Spirit without previous washing 

 with water. 



The differentiation in 90 p. c. Alcohol will vary from 10 

 to 30 minutes, according to the nature of the section. 



When sections are to be also treated with one of the Plas- 



* 



matic stains, the counterstaining will of course be doi^pre- 

 vious to the dehydration in Absolute Alcohol. 



(i.) METHYLENE BLUE. 



Methylene Blue, 0'25 grm. Eectified Spirit, 20 cc. ; Distilled 

 Water, 80 cc. 



To stain the nuclei, sections are placed in this solution for 

 5 minutes, rinsed thoroughly in Distilled Water, differentiated 

 in 90 p. c. Alcohol, dehydrated, cleared and mounted in 

 Balsam. 



(ii.) METHYL GREEN. 



Methyl Green, 0'5 grm. ; Eectified Spirit, 20 cc. ; Distilled 

 Water, 80 cc. 



To stain the nuclei, sections are placed in this solution for 



