26 PRACTICAL MICROSCOPY. 



allow the whole to remain exposed to the air for one week, and thea 

 filter. 



The solution should always be filtered before using. Keep the 

 filter paper in a funnel, and use it as a stopper for the bottle. The 

 dye improves in strength of color for two or three weeks. 



Should the solution, which is of a beautiful purple or violet color, 

 at any time turn red, a small piece of common chalk may be added. 

 This will restore the color by neutralizing the acidity. A few crystals 

 of alum should always be kept in the bottle to insure saturation. 



Prepared as above, the dye will keep perfectly for at least eight 

 months, and gives a permanent stain. 



BOKAX-CARMINE STAINING FLUID. 



To eight ounces of a saturated aqueous solution of borax (borate 

 of soda) add one drachm of the best No. 40 carmine (previously 

 rubbed into a paste with a little water). In order to insure satura- 

 tion, some borax crystals should always be left undissolved at the 

 bottom of the bottle. Agitate frequently, and, after twenty-four 

 hours, add fifteen drops of liquor potass. 



Always filter or decant before using. It will keep indefinitely, im- 

 proving, to a certain extent, with age. 



EOSIN SOLUTION. 



Alcohol, 2 ounces. 



Eosin, 1 drachm. 



This will give a saturated solution. 



PICRIC ACID SOLUTION. 



Picric acid, i ounce. 



Water, 4 ounces. 



The acid is in excess, insuring saturation. 



NITRATE OF SILVER SOLUTION. 



Nitrate of silver, o grains. 



Distilled water, .... 4 ounces. 



If the water be pure, light will have no effect upon the solution. 



