14 



the flame, and then proceed to stain either with No. i 

 or No. 2 solution, leaving it on for about five minutes ; 

 then run it off, removing the superfluous stain by waving 

 it for a moment or two in water, and put on the No. 4 

 solution, which fixes the stain in the organism. After 

 leaving this on for about two or three minutes, run it 

 off and treat with alcohol, which takes the stain out of 

 everything except the various organisms which have 

 taken it up ; in fact, it will begin to remove it from 

 the cryptococci also if left on more than a few seconds. 

 Having now decolourized put on the No. 6 solution (the 

 counter stain), and after having left this on for about 

 three minutes run it ofi^, wash in water, and dry. The 

 specimen is now ready to be examined under the micro- 

 scope and may be mounted in Canada balsam. 



Gram-fVeigen-Kuhne method. 



1. Stain with the No. 3 solution for five to fifteen 

 minutes. 



2. Wash In water. 



3. Dry with blotting paper. 



4. Treat with the No. 5 iodine solution for one 

 to two minutes. 



5. Dry with blotting paper. 



6. Decolourize with aniline oil until no more colour 

 is removable. 



7. Treat with zylol, and mount in Canada balsam. 

 Sections may be stained by this method, but they first 

 require staining for half-an-hour with lithium carmine 

 solution (carmine 2*5 to 100 parts of saturated solution 

 of lithium carbonate). Diff"erentiate in alcohol or hydro- 

 chloric acid alcohol, then wash in water and proceed as 

 before, 



