64 PRACTICAL HISTOLOGY. 



2. Frey's Carmine. Ordinary carmine has two drawbacks : it 

 is apt to undergo putrefaction, and as the ammonia escapes the 

 carmine is precipitated. 



Carmine . . . . .0.3 gram. 



Distilled water . . . . 30 cc. 



Dissolve the carmine in the water, adding ammonia drop by drop 

 until solution is complete. Then add 



Glycerine . . . . 30 cc. 



Alcohol . . . . 4 ,, 



and shake the mixture. Keep it in a stoppered bottle. It has 

 no advantage, as far as coloration is concerned, over ordinary 

 carmine, but it can be kept for a long time unchanged. 



3. Alcoholic Borax Carmine (Grenacher). 



Carmine ...... 3 grams. 



Borax . . . . . . 4 



Water . . . . . . . 100 cc. 



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

 quickly dissolved, especially with the aid of gentle heat. Add 100 

 cc. of 75 per cent, alcohol, and filter. 



4. Watery Borax-Carmine. Rub up in a mortar 8 grams borax 

 with 2 grams carmine, and add 15000. water. After twenty-four 

 hours decant and filter. Tissues to be stained in bulk e.g., after 

 hardening with corrosive sublimate are placed for twenty-four 

 hours or longer in this fluid. They are then transferred to acid 

 alcohol (i per cent. HC1 in 70 per cent, spirit for twenty-four 

 hours), and then into alcohol. 



If it be desired to stain in bulk without bringing the tissue into 

 contact with water, then use : 



5. Carmine-Solution (P. Mayer). For staining in bulk, and also 

 for sections, Mayer recommends the following : Suspend 4 grams 

 carmine in 15 cc. water, and then add 30 drops hydrochloric acid, 

 gently heating the mixture. Add 95 cc. alcohol (85 per cent.) and 

 boil. Neutralise with ammonia and on cooling filter. 



6. Borax Carmine (Grenacher). 



Carmine ..... I gram. 



Borax ...... 2 grams. 



Distilled water . . . . . 200 cc. 



The borax dissolves the carmine. The whole is placed in a 

 porcelain capsule and heated to boiling, when the fluid becomes of 

 a dark-purplish or bluish-red. Add a few drops of 5 per cent, 

 acetic acid, until the colour becomes more like that of carmine 

 dissolved in ammonia. Let it stand for twenty-four hours, and 



