FORMULAS FOR REAGENTS 391 



Heidenhain's iron-haematoxylin. — 



This stain was introduced by Heidenhain in 1892 and,forcytological 

 work and much morphological work, has become the most widely and 

 efficiently used of all stains. Two solutions are used, and they are 

 never mixed : 



A. 1^ to 4 per cent aqueous solution of ammonia sulphate of iron. 

 Use the ferric (violet) crystals, not the ferrous (green) crystals. 



B. I per cent solution of haematoxylin in distilled water. 



The crystals of haematoxylin will dissolve in the distilled water in 

 about 10 days; the stain reaches its greatest efficiency in about 6 

 weeks. About 3 months from the time it is made up, it begins to de- 

 teriorate. A stain made by dissolving the crystals in strong alcohol 

 and then diluting with water so as to get a practically aqueous solu- 

 tion is not so good. 



Greenacher's borax carmine. — 



Carmine 3 g. 



Borax 4 g. 



Distilled water 100 c.c. 



Dissolve the borax in water and add the carmine, which is quickly 

 dissolved with the aid of gentle heat. Add 100 c.c. of 70 per cent alco- 

 hol and filter (Stirling). 



Alum carmine. — 



A 4 per cent aqueous solution of ammonia alum is boiled 20 minutes 

 with 1 per cent of powdered carmine. Filter after it cools (Lee). 



Alum cochineal. — 



Powdered cochineal 50 g. 



Alum 5 g. 



Distilled water 500 c.c. 



Dissolve the alum in water, add the cochineal, and boil; evaporate 

 down to two-thirds of the original volume and filter. Add a few drops 

 of carbohc acid to prevent mold (Stirling). 



Picro-carmine. — 



Picro-carmine (picro-carminate of ammonia) 1 g. 



Water 100 c.c. 



Myer's carmalum. — 



Carminic acid 1 g. 



Alum 10 g. 



Distilled water 200 c.c. 



