ii6 



I 86. Paracarmine ( Mayer) . Formula : Canninic acid, i gram ; alumi- 

 num chlorid, .5 gram ; calcium chlorid, 4 grams ; 70% (67%) alcohol, 100 c. c. 

 Allow it to stand a day or so, shaking occasionally until the carminic acid has 

 quite dissolved, and then filter. 



This is an excellent carmine stain for in toto staining. The tissue may be 

 stained i-several days (l week), then washed in 67% and 82% alcohols to re- 

 move the excess of staining fluid. A red nuclear stain, more opaque than 

 borax carmine. It does not over-stain readily, and since it is an alcoholic so- 

 lution ( 70% ) it is quite penetrating and may be allowed to act for a greater 

 length of time, being thus suited for staining in toto objects of considerable 

 size. 



^ 87. Hcl. carmine. Formula : Carmine, 2 grams ; concentrated hydro- 

 chloric acid, 3 c. c. ; 70% alcohol, 100 c. c. Boil gently for 15-20 minutes to 

 dissolve the carmine ; cool and filter. ^ 



This is a strong carmine stain, quite suitable for sections, especially such 

 as stain with difficulty. It may also be employed for staining in toto. Stain 

 sections from alcohol or water for 5-15 minutes ; rinse away the superfluous 

 stain with 67% (70%) alcohol and differentiate for a few seconds to a minute 

 with acid alcohol (95% alcohol 100 c. c. , concentrated hydrochloric acid \ c. c). 

 Wash away the acid alcohol with ordinary 95% alcohol. If a pure nuclear 

 stain is not desired the differentiation may be omitted. 



Picric alcohol may be used as a counter stain, and in that case diflferentia- 

 tion is ordinarily not required. 



\ 88. Picro-carmine. Employ a %% aqueous solution of the dry picro- 

 carmine, made according to Ranvier's formula. Stain sections yi-\ hour or 

 longer and rinse well in water. If the sections are over-stained they may be 

 differentiated by means of acid alcohol as used with Hcl. carmine. 



While it is itself a good stain, it may be used with hematoxylin as a coun- 

 ter-stain with good results. It is an alkaline solution, and the hematoxylin 

 stain is intensified. As employed in this way, stain in hematoxylin the usual 

 length of time, rinse in water and stain 2-3 hours in the picro carmine solution ; 

 rinse in water ; dehydrate, clear, and mount in balsam. As used in this way, 

 there is afforded an excellent stain for developing bone. 



\ 89. Safranin. Formula (Babes') : Concentrated aqueous solution of 

 safranin, l part ; concentrated alcoholic solution of safranin, i part. 



Stain sections 1-4 hours, or over night ; wash away excess of stain with 95% 

 alcohol, differentiate with acid alcohol (95% alcohol, 100 c.c, hydrochloric 

 acid, yV^.c. ) for a few seconds, rinse with 95% alcohol and clear in carbol- 

 xylene or bergamot oil. If a pure nuclear stain is not required, the differentia- 

 tion may be omitted. This gives a good stain with tissue fixed in Hermann's 

 or Flemming's fluid. It is a brilliant, transparent red. (See § 99). 



\ 90. Gentian violet. Formula : A concentrated solution in distilled 

 water. Stain (paraffin) sections from water for 5-10 minutes, rinse in water, 

 dehydrate and differentiate with 95% alcohol and complete the differentiation 

 with clove oil. When the differentiation is sufficient, clear with bergamot oil 



