40 



distilled water, 95 c. c.). (c) Differentiator; the ferric alum mordant, preferably 

 diluted several times. An excellent stain, especially for cytological work. It 

 may be used after any fixer. 



The steps necessary are: (1) Mordanting 1 to 24 hours; (2) rinse the, sec- 

 tions in water 10 to 30 minutes; (3) stain for 3 to 24 hours; differentiate slowly 

 and control it under the microscope. The slides may be alternately dipped into 

 the ferric alum solution for a few seconds and then into tap water. (4) Wash 

 in running water 15 to 60 minutes. The ferric alum mordant may be used several 

 times as well as the hematoxylin solution whose staining quality improves up to 

 a limit by use. 



95. Copper Hematoxylin (Weigert). Formula: Mordant; 3.5% aqueous 

 solution of copper acetate; Stain; 10% alcoholic solution of hematoxylin 10 c. c.; 

 distilled water, 90 c. c.; saturated solution lithium carbonate, 1 c. c. Differentia- 

 tor; potassium ferricyanide, 2.5 grms., borax, 2 grms.; distilled water, 200 c. c. 

 Designed for staining the myelinic sheath of medullated nerve fibers ( 199) but 

 useful for other purposes. 



The steps are: (1) mordanting for 1 to 24 hours, (2) rinsing the sections 

 in water 10 to 30 minutes, (3) staining for 3 to 24 hours, (4) differentiate slowly 

 controlling the action under the microscope. (5) Wash in running water 30 

 minutes or longer. The mordantage may be given in bulk if desired. As usually 

 employed with tissue fixed in chrome fixers, the stain is strictly a chrome-copper 

 hematoxylin. Other differentiators may be used if desired. Mount in neutral 

 balsam. 



96. For Mallory's phospho-molybdic hematoxylin, Heidenhain's vanadium 

 hematoxylin, and other hematoxylin formulae of occasional usefulness, consult 

 the works on technique (p. 90). 



97. Carmine Stains'. Like hematoxylin, the carmine stains depend 

 upon an acid staining principle, carminic acid, which in combination with 

 bases gives a red nuclear stain of value. The metals usually employed in carmine 

 formulae are aluminium, calcium, strontium, iron. Carmine itself is (Liebermann) 

 a combination of carminic acid with aluminium, calcium, and protein. It is 

 soluble in acids and alkalis. The necessary mordant is not so often employed 

 in a separate solution as is the case with hematoxylin. See, however, iron carmine 

 [6, 30]. 



98. Carmalum (Mayer's) Formula: Carminic acid, 1 grm.; potas- 

 sium alum, 10 grms.; distilled water, 200 c. c. Dissolve with heat (if neces- 

 sary). Filter. Add 1 c. c. formalin as a preservative. It may be used for 

 in toto or for section staining. 



Stain sections 5 to 30 minutes or as long as necessary. Rinse tissue before 

 staining with distilled (not tap-) water. 



99. Borax carmine. (Grenacher). Formula: Borax 4 grams;' carmine, 3 

 grams; water, 100 c. c.; allow the mixture to stand for several days, shaking 

 occasionally when most of the carmine will have dissolved; filter and add 100 

 c. c. of 70% alcohol. Let the mixture remain for several days, filter again and 

 the solution is ready for use. 



This is a good carmine stain for in toto staining. Stain objects in toto for one 

 to several days, according to size; remove to 67% (70%) alcohol, acidulated 



