STAINI\<. 



carefully in tap water and transferred to 0.5 per cent, aqueous 

 solution of hsematoxylin and left for from twenty-four to 

 thirty-six hours. After being washed in water they are differ- 

 entiated in the iron-alum solution. They are then washed for 

 one-fourth to one hour in running tap water, dehydrated, 

 cleared, and mounted in balsam. This method demonstrates 

 the centrosomes, chromatin, secretory capillaries (bile capil- 

 laries), and microsomes. The protoplasm may be counter- 

 stained in a dilute solution of acid rubin. 



Anilin dyes (for classification, see section on Blood). 



Safranin is an excellent nuclear stain. One way of prepar- 

 ing it is to dissolve 1 gramme of safranin in 100 grammes of 

 absolute alcohol, and after several days to add 200 cc. of dis- 

 tilled water. Sections stained for twenty-four hours in this 

 solution should be differentiated in absolute alcohol. Sections 

 of tissues fixed in Flemming's fluid may be differentiated in 

 absolute alcohol which contains 1 gramme of HC1 to 1000 

 grammes of alcohol. The chromatin of the nucleus is colored 

 a bright red. 



Thionin is a valuable anilin dye. In 1 per cent, aqueous 

 solutions it colors nuclei (chromatin) blue in a few minutes, 

 and mucus red. 



Vesuvin in 2 per cent, aqueous solutions is a brown nuclear 

 stain. About five minutes are required for its action. 



The most common double stains or multiple stains in use 

 are the following : 



Hcematoxy I'm- eosin and Hozmalum-eosin. Sections stained 

 in hsematoxylin or h&malum are washed in water, and stained 

 in a weak aqueous solution of eosin (1 part of eosin to 1000 

 parts of water). After washing in water, and for from three to 

 five minutes in 96 per cent, alcohol the sections are cleared in 

 creosote and mounted in balsam. This method stains the 

 nuclei blue and the protoplasm pink. Congo-red may be used 

 instead of eosin. The ha3matoxylin is used often in stronger 

 solutions for five minutes, and then the sections should be 

 decolorized in acid alcohol, and made blue again in ammonia- 

 water. 



