MICRO-ORGANISMS. 65 



the Aniline, and treat in a similar way with Xylol for about 

 a minute, and mount in Balsam. 



Previous to this process for bacteria, the nuclei in the sec- 

 tions may be stained with Carmine (p. 28). 



Kuline's Modification of Gram's Method. 



Kiihne uses Fluorescine Alcohol after Gram, in the place of 

 Alcohol for washing, and adopts Weigert's Aniline for clear- 

 ing ; he also stains the nuclei with Carmine (nuclear staining, 

 p. 28), previous to commencing the following process. 



Sections are stained for 5 minutes in the solution of Methyl 

 Violet, diluted one-sixth with a 1 p. c. aqueous solution of 

 Ammonium Carbonate, or in the Victoria Blue solution ; they 

 are then rinsed thoroughly in Water, and transferred to Gram's 

 solution from 2 to 3 minutes, again rinsed in water, and the 

 excess of stain extracted in Fluorescine Alcohol. They are 

 then passed through pure Alcohol, Aniline, Ethereal Oil, and 

 Xylol, and mounted in Balsam. 



WITH METHYLENE BLUE. 



Lbffler's Universal Staining Fluid. 



Concentrated Alcoholic solution of Methylene Blue, 30 cc. ; 

 Solution of Caustic Potash (1 in 10,000 of water), 100 cc. 

 This mixture will not keep good for many days, and should 

 be filtered each day before use. 



Loffler found that most bacteria stained better in this solu- 

 tion than in the weaker solution used by Koch for the Tubercle 

 bacillus. 



Sections are placed in this solution for a few minutes 

 (Tubercle sections for some hours) ; remove excess of stain by 

 immersion in very weak Acetic Acid (J p. c.) for a few seconds, 



