88 CARMINE STAINS. 



Boric Acid Alum-Carmine, ABCANGELI, Ibid. 

 Salicylic Acid Alum-carmine, ABCANGELI, Ibid. 

 Salicylic Acid Carmine, ABCANGELI, Ibid. 

 Picric Acid Carmine, ABCANGELI, Ibid. 



Picric Acid Carmine, MINOT (see Whitman's Methods in Mie. Anat., 

 p. 42). 



B. ALCOHOLIC CARMINE STAINS. 



163. Alcoholic Borax- Carmine (G-RENACHER, Arch. f. mik. 

 Anat., xvi, 1879, p. 466, et seq.). Take a concentrated solution 

 of carmine in borax solution (2 to 3 per cent, carmine to 4 per 

 cent, borax) ; dilute it with about an equal volume of 70 per 

 cent, alcohol, allow it to stand some time, and filter. Or, the 

 mixture of carmine and borax solution is alloiued to stand for 

 two or three days and occasionally stirred ; the greater part of 

 the carmine will dissolve. To the solution is added an equal 

 bulk of 70 per cent, alcohol ; the mixture is allowed to stand 

 for a week, and then is filtered. If on keeping more carmine 

 is deposited, it must be refiltered. 



Preparations should remain in the stain until they are 

 thoroughly penetrated (for days if necessary), and then be 

 brought (without first washing out] into alcohol acidulated 

 with 4 to 6 drops of hydrochloric acid to each 100 c.c. of 

 alcohol. They are left in this until they are thoroughly pene- 

 trated, and may then be washed or hardened in neutral alcohol. 

 Four drops of HC1 is generally enough. Three drops I find 

 not quite sufficient. The stained objects should remain in the 

 acidulated alcohol till they acquire a bright transparent look 

 (three to six hours) . 



For delicate objects, and for very impermeable objects, it 

 may be well to increase the proportion of alcohol in the stain : 

 it may conveniently be raised to about 70 per cent. The 

 washing out, or decolouration, will be enormously facilitated 

 if picric acid be added to the acidulated alcohol, but in this 

 case the proportion of HC1 should be reduced. It should not 

 exceed that of 1 drop of HC1 to 100 c.c. of alcohol, and the 

 decolouration should be carefully watched, as the stain may 

 easily be entirely washed out in this mixture. For this reason, 

 the process is not to be recommended in general ; I merely 

 mention it because it is well that the student should be 

 acquainted with the reaction. 



This stain is probably by far the most popular of any for 



