FORMULA. 



When not stated the solids are reckoned in grains and the fluids in cubic cen- 

 timeters. Water is understood when no particular solvent is mentioned. 



STAINS. 

 GENERAL AND MISCELLANEOUS. 



Alcoholic Solutions of Anilin Stains. 

 These should be saturated solutions, made 

 preferably with Griibler's stains and absolute al- 

 cohol. In well-stoppered bottles they keep in- 

 definitely. 



Watery Solutions of Anilin Dyes. 



These do not keep long and must be made up 

 fresh each time. If made directly from the dry 

 powder or crystals, rather than from the alcoholic 

 solution, the resulting fluid should be passed 

 through filter paper before using. Watery solu- 

 tions are usually made by adding the alcoholic 

 solution to distilled water in any strength de- 

 sired. Usually a few drops of the alcoholic 

 solution to 5 or 10 cc. of water is sufficient. 



Anilin Water. 



Anilin water is made by shaking thoroughly 

 one part of anilin in 20 parts of distilled water 

 and filtering it clear by passing one or more 

 times through filter paper moistened with water. 

 It should be prepared fresh each time. Anilin, 

 known also as anilin oil, is a colorless, oily- 

 looking fluid. It oxidizes to a brown color if 

 exposed to the air, and it should therefore be 

 kept in a close-stoppered bottle in the dark. 

 The brown fluid is still usable, at least for some 

 purposes. 



Ziehl's CarboI-Fuchsin. 



Fuchsin (basic) I 



Absolute alcohol 10 



Carbolic acid (5 per cent sol. in 



water) 100 



The fuchsin should first be dissolved in the 

 alcohol and then the two fluids mixed. A pow- 

 erful and much-used stain. 



Ehrlich's Anilin-Water Gentian Violet. 



Alcoholic solution of gentian violet 



(saturated) 5 



Anilin water 100 



This should be used as soon as prepared. It 

 does not keep well. 



Flexuer's Anilin Gentian Violet. 



Anilin oil 2 



Alcohol, 95 per cent 5 



Saturated alcoholic (absolute) solu- 

 tion of gentian violet 8 



Distilled water So 



Mix well and filter. 



Ehrlich-Weigert Anilin Methyl Violet. 

 Alcoholic solution of methyl violet 



(saturated) n 



Absolute alcohol 10 



Anilin water 100 



Does not keep well. 



Anilin Fuchsin. 



Prepared in the same way as Ehrlich's anilin 

 gentian violet 



Ziehl-Nielson's Stain. 



Used chiefly as a means for identifying tuber- 

 culosis. The cover-glass bearing the specimen 

 is floated for 3 to 7 minutes on carbol-fuchsin 

 which is heated until steam begins to appear. 

 It is then washed in distilled water, plunged into 

 10 per cent nitric or sulphuric acid long enough 

 to decolorize (a very short time). It is then 

 passed through 60 per cent alcohol for a few 

 seconds (just long enough to remove the stain 

 from the background), washed thoroughly in 

 water, dried, and mounted in balsam. The 

 cover-glass preparation may be obtained also by 

 dropping some of the stain upon it and holding 

 it over the flame. This method is more eco- 

 nomical of stain and time and less mussy than 

 the preceding. 



Friedlaender's Stain. 



This has been used so far mostly for identify- 

 ing the tubercle organism in sputum. It is 

 made as follows : A few drops of carbol-fuchsin 

 are placed on the prepared cover (which has 

 been gently flamed) and heated over a flame 

 until the fluid steams. The cover is then 

 washed in distilled water, and plunged for a half 



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