5 2 ME THODS F EX A MINA TION. 



which the fluid may be filtered, and which serves to keep out 

 dust from the bottle. 



Three or four small filter ring-stands. 



A large bottle of three-quarter per cent, salt solution, which has 

 been carefully boiled. 



Acetic acid ; one in four. 



Glacial acetic acid. 



Nitric acid, pure. 



Hydrochloric acid, pure. 



Carbonate of potash solution. 



Caustic potash solution, forty per cent. 



Strong ammonia. 



Ether. 



Chloroform. 



Alcohol, methylated. 



Alcohol, anhydrous. 



Perchloride of mercury solution, one per cent. 



Saturated or ten per cent, solution of acetate of potash. 



Osmic acid, half per cent., kept in a wide-mouthed bottle covered 

 with brown paper. 



A saturated solution of aniline oil in water. Prepared as follows : — 

 Aniline oil, . . . . i part. 



Distilled water, . . .3 parts. 



Shake well every half hour for three or four hours, and 

 decant the water as the oil settles to the bottom. The com- 

 mercial aniline may be used instead of the pure form, as it is 

 only about one-twelfth of the price, and answers almost as well. 



Watery solutions of the aniline dyes, especially gentian violet, 

 methyl violet, methyl blue, chrysoidin, vesuvin, and magenta. 

 Any of these may be used as a half to two per cent, solu- 

 tion. They should be kept in the filter bottles, in each of 

 which a crystal of thymol should be placed. 



Saturated alcoholic solutions of gentian violet, fuchsin, eosin, and 

 other dyes, if necessary. These should be kept in well stop- 

 pered bottles, but should be filtered before they are used. A 

 crystal of thymol should be added. 



Weigert's picro-carmine solution (Griibler, Leipzig). 



