22 MANUAL OF HISTOLOGY. 



in this way. It is therefore desirable, after using the acid, to 

 wash thoroughly in alcohol or water. 



Borax carmine (Arnold's formula). The following method 

 is given by Dr. M. N. Miller as the one in use by students in 

 the histological laboratory of the New York University. It 

 originated with Prof. J. W. S. Arnold. A saturated solution 

 of borax is prepared in a wide-mouthed pint bottle. The borax 

 should be in some excess. "No. 40" carmine is now added 

 to the solution under constant agitation, until after a while it 

 no longer dissolves, and an excess remains at the bottom of the 

 vial, mingled with the crystals of borax. After twenty-four 

 hours the supernatant fluid is decanted. To this clear portion 

 f. ^ij- of alcohol are added, and f. 3 j. of caustic soda solution 

 (U. S. P.). The staining solution is now ready. Or, the alco- 

 hol may be omitted (Arnold), and the liquid evaporated to dry- 

 ness ; the red amorphous mass is then powdered. Of this, 

 15 grains are placed in an ounce of water, to which f. 3 j. of 

 alcohol is added. 1 



Sections, after staining, should be washed in alcohol to re- 

 move the superfluous coloring fluid, and then transferred to a 

 saturated solution of oxalic acid in alcohol to fix the color. 

 The oxalic acid is then washed out in alcohol ; finally the sec- 

 tions are cleared up in oil of cloves, and mounted in balsam or 

 dammar. 



Double staining by borax carmine and indigo carmine. 

 Drs. W. T. Norris and E. O. Shakespeare, of Philadelphia, 

 have recommended a method which is a modification of Mer- 

 kel's. Two staining fluids are made, one red and the other 

 blue. The red one contains carmine, gr. 7J ; borax, 3 ss. ; dis- 

 tilled water, 1 j. The blue contains indigo carmine, 3 ss. ; bo- 

 rax, 3 ss. ; and distilled water, 3 vij. 



After thorough trituration the ingredients are mixed and 

 left in a vessel ; the supernatant fluid is then poured off. The 

 sections, if previously hardened in bichromate, picric acid, or 

 chromic acid, should be well washed ; they then are to be 

 placed for a few minutes in a mixture (equal parts) of the red 

 and blue fluids, then transferred, without washing, to a satura- 

 ted solution of oxalic acid and allowed to remain in it rather 

 less time than in the staining fluid. When sufficiently bleached 



1 [This preparation of borax carmine is the best that I have ever used. T. E. S.] 



