STAINING. 



43 



Delafield's Hematoxylin : 



Hematoxylin crystals 



Absolute alcohol 25 c.c. 



Ammonia alum, saturated aqueous solution 400 " 



Alcohol, 95^ loo " 



Glycerin loo " 



Dissolve hematoxylin crystals in absolute alcohol and add to the alum solution, after 

 which place in an open vessel for four days, filter, and add the 95 % alcohol and glycerin. 



After a few days it is again filtered. This fluid is either used pure or 

 diluted with distilled water. Staining is the same as with Bohmer's hema- 

 toxylin. 



Friedlander's Glycerin-hematoxylin : 



Hematoxylin crystals 2 gm. 



Potassium alum 2 " 



Absolute alcohol 100 c.c. 



Distilled water 100 " 



Glycerin 100 " 



Dissolve the hematoxylin crystals in the absolute alcohol and the alum in the water ; 

 mix the two solutions and add the glycerin. 



The mixture is filtered and exposed for several weeks to the air and 

 light, until the odor of alcohol has disappeared, and then again filtered. 

 It stains very quickly. Sections are afterward washed in water and are 

 placed for a short time in acid alcohol if the nuclei are to be especially 

 brought out. 



Ehrlich's Hematoxylin : 



Hematoxylin crystals 2 gm. 



Absolute alcohol 60 c.c. 



Glycerin \ saturated with .... 60 " 



Distilled water / ammonia alum .... 60 " 



Glacial acetic acid 3 " 



The solution is to be exposed to light for a long time. It is ready for use when it 

 acquires a deep-red color. 



Stain as above. 



Hemalum (P. Mayer, 91). i gm. of hematein is dissolved 

 by heating in 50 c.c. of absolute alcohol. This is poured into a solu- 

 tion of 50 gm. of alum in i liter of distilled water and the whole well 

 stirred. A thymol crystal is added to prevent the growth of fungus. 

 The advantages of hemalum are as follows : The stain may be used im- 

 mediately after its preparation, it stains quickly, never overstains, 

 especially when diluted with water, and penetrates deeply, making it 

 useful for staining in bulk. After staining, sections or tissues are washed 

 in distilled water. 



Acid Hemalum. To the above hemalum solution is added 2% of 

 glacial acetic acid. Stains even more rapidly than hemalum, and gives 

 excellent nuclear differentiation. Wash sections in tap-water. 



Heidenhain's Iron Hematoxylin. Good results, particu- 

 larly in emphasizing certain structures of the cell (centrosome), are ob- 

 tained by the use of M. Heidenhain's iron hematoxylin (92. 2). Tissues 

 are fixed in saline sublimate solutions, alcohol, or Carnoy's fluid. Very 

 thin sections (in case of amniota not over 4^) are fixed to the slide with 

 water and put, into a 2.5% aqueous solution of ammonium sulphate of 

 iron for four to eight hours (not longer). After careful rinsing in water, 

 the sections are brought into a solution of hematoxylin prepared as fol- 

 lows : Hematoxylin crystals i gm., absolute alcohol 10 c.c., and dis- 



