TUBERCULOSIS 83 



1. Ziehl-N eelsen method. One grm. of fuchsia is dis- 

 solved in 10 c.c. alcohol and 100 c.c. 5 per cent, phenol 

 water and the solution is filtered. By means of a 

 pipette, a liberal quantity of this staining fluid is 

 dropped on the cover glass which is held by pincers 

 above a flame a couple of minutes until the fluid 

 boils briskly, but without drying. Then the cover glass 

 is rinsed with water and treated for a few seconds 

 with 25 per cent, sulphuric acid and again rinsed with 

 water. If the red color is still distinct, the treatment 

 with acid is repeated and the cover glass is rinsed 

 carefully with a little alcohol. Finally, a few drops of 

 watery solution of methylene blue are dropped upon it, 

 after which it is again rinsed with water and mounted. 



2. Kitt's method. To 100 c.c. saturated anilin water 

 are added 1 c.c. of a 1 per cent, sodium hydrate solution 

 and 4 to 5 grm. of fuchsin. Or, the above mentioned 

 phenol-fuchsin solution may be used. The cover glass is 

 treated as described above, then rinsed and dipped for 

 one-half minute in a fluid consisting of 50 c.c. alcohol, 30 

 c.c. water and 20 c.c. nitric acid, to which has been 

 added as ranch methylene blue as the fluid will dissolve. 

 Finally, the slide is riased with water. 



3. CsaplewsM's method. The staining is done by 

 heating with phenol-fuchsin solution as given above. 

 Allow the staining fluid to run off and, without rinsing, 

 dip the cover glass six to ten times into a concentrated 

 alcoholic solution of fluorescein (1 grm. in 100 c.c. alco- 

 hol). The double staining comes from repeatedly 

 dipping the cover slips in concentrated alcoholic solution 

 of methylene blue (5 to 100) ; then they are rinsed in 

 water. By this method, a decoloration of tubercle bacilli 

 is avoided with certaiaty. 



In all cases, the preparation is mounted and ex- 



