Appendix B : Some Standard Reagents and Their Uses 173 



31. Bismarck Brown. Boil one gram of the stain in 100 c.c. 

 of water, filter, and add 30 c.c. of strong alcohol. Bismarck 

 brown is a nuclear stain which does not overstain although it acts 

 rapidly. After staining wash in 95 per cent, or absolute alco- 

 hol. This stain is also used in aqueous solution for intra vitam 

 staining; the nucleus of the living cell may thus be colored. It 

 has been used as an intra vitam stain mostly in the study of 

 infusoria. The stain may be fixed by means of a 0.2 per cent, 

 chromic acid solution, but this, of course, destroys the life of the 

 cells. 



32. Borax-Carmine (Grenadier's). See chap, i, reagent 12. 



33. Bordeaux Red. See chap, i, reagent 15. 



34. Carmalum. (Mayer's) . 



Carminic acid 1 gram 



Alum 10 grams 



Distilled water 200 c.c. 



Dissolve with heat and filter the solution when cold. Add a 

 few crystals of thymol or a little salicylic acid to prevent the 

 formation of mold. Carmalum is one of the best stains for stain- 

 ing objects in bulk and will follow almost any fixing reagent, 

 even osmic acid. If the object has an alkaline reaction it does 

 not stain so well. Washing is done in water. 



35. Carmine (Beale's). 



Powdered carmine 1 gram 



Ammonia 3 c.c. 



Pure glycerin 96 c.c. 



Distilled water . . . 96 c.c. 



Alcohol, 95 per cent 24 c.c. 



The ammonia and part of the water are first mixed and the 

 carmine dissolved in the mixture. The remaining water is added 

 and the solution is left in an open dish until the ammonia has 

 almost evaporated. The alcohol and glycerin are then added. 

 For staining, equal parts of the stain and glycerin are used. The 

 staining is carried on for 24 hours under a bell jar in an uncovered 

 dish. A second open dish containing acetic acid is placed under 

 the bell jar. After staining, the sections are washed in water, 



