54 MANUAL OF BACTERIOLOGY. 



ful preparations can be obtained according to this or the 

 Gram method when the sections have previously been 

 stained in carmine; the nuclei will then be colored red, 

 bacteria violet. 



Tubercle bacilli may be stained in sections as follows : 



(a) Use carbol-fuchsin, or aniline-water gentian-violet 

 for one-half to two hours with very gentle warming, or 

 over night without warming. 



(b) Wash in water. 



(c) Decolorize with some one of the decolorizing agents 

 mentioned in connection with the staining of tubercle ba- 

 cilli in cover-glass preparations, preferably 3 per cent, hy- 

 drochloric acid alcohol. Decolorization must be continued 

 until the red color has disappeared, which requires one-half 

 to several minutes. 



(d) Wash in alcohol. 



(e) Wash in water. 



(/) Use hematoxylin as a contrast-stain for fuchsin 

 preparations, and carmine for gentian-violet preparations. 

 (It is better to stain with carmine first of all and before 

 staining the bacilli. The carmine is not affected by the 

 subsequent treatment. ) 

 (g) Wash in water. 

 O) Alcohol, 

 (i) Xylol. 

 (/) Balsam. 



Nuclear stains, which may be used as contrast-stains for 

 sections : 



DELAFIELD'S HEMATOXYLIX. 



Hematoxylin crystals 4 grams. 



Alcohol 25 c.c. 



Ammonia alum 50 grams. 



Water 400 c.c. 



Glycerin TOO c.c. 



Methyl alcohol 100 c.c. 



