60 THE MICROSCOPE. [April, 



any other cell contents which the bleaching fluid would dissolve. 

 Certain resinous drugs, such as pellitory, must not be mounted 

 in Canada balsam, which would dissolve out the resin; in such 

 cases glvcerin jelly, containing carbolic acid, arsenic, or some 

 other preservative, should be used. This is best used, not with 

 a rod. but filtered, while hot and liquid, through cotton wool 

 directlv onto the slide. To keep glycerin in is a very difficult 

 matter. Gold size which is at least ten years old and quite 

 " tacky " or sticky is a very good cement, but it should be touched 

 over about every five years. 



Certain black cements are very liable to run into the Canada 

 balsam and spoil the sections. 



VEGETABLE STAIXS. 



[From Pharmaceutical Journal and Transactions.] 



Hsematoxylin. — The formula for Ehrlich's ammoniated 

 haematoxvlin is: Hematoxylin, 2 grams, and ammonium carbo- 

 nate. 0.4 gram, are dissolved in proof spirit, 40 c. c, and ex- 

 posed to the air in a shallow dish for 24 hours. The volume is 

 then made up to 40 c. c, with proof spirit, which is warmed, if 

 necessary, to dissolve any separated crystals. Ammonia alum, 2 

 grams, dissolved in distilled water, So c. c. is then added ; together 

 with glycerin. 100 c. c, rectified spirit, Soc. c, glacial acetic acid, 

 10 c. c. The solution is ready to be diluted for use straight 

 way and does not deteriorate by keeping. Sections when 

 stained with it are of a violet color, but this may readily be 

 changed to blue by washing in an aqueous solution of sodium 

 bicarbonate (\ grain in 1 ounce). As soon as the color is satis- 

 factory, the sections should be transferred to 70 percent, alcohol, 

 for if kept in water the color is apt to fade. Over-staining may 

 be remedied bv the addition of one-tenth to one half-per cent, of 

 strong hydrochloric acid to the alcohol and subsequent wash- 

 ing- with the sodium bicarbonate solution alreadv mentioned. 



Plasmatic Stains. — Alcohol must be removed from the sec- 

 tions by placing them for a minute in distilled water, after which 

 they may be transferred to the plasmatic stain. To follow haema- 

 toxylin. this may be water, soluble eosin (1 gram in 40 c. c. of 

 alcohol and 160 c. c. of distilled water), erythrosin (same 

 strength as eosin). or orange (2 grams in 20 c. c. of alcohol, and 

 So c. c. of distilled water). After using carmine, picric acid (1 

 gram in 100 c. c. of 70 per cent, alcohol) affords a suitable con- 

 trast. In each instance, afterwards wash with 90 percent, alcohol. 



