STAINING SPORES AND FLAGELLA 61 
of culture was added to the water, many will be found scattered 
within the ring, some of them isolated so they can be easily 
studied. The flagella should appear as fine, hairlike appendages 
radiating from the bacteria. A little practice with this will enable 
one to make good preparations altogether free from background. 
92. Mordants and stains. Different mordants and staining 
solutions may be used. Those of Loeffler or Pitfield give the 
most uniform and satisfactory results. 
LOEFFLER’S MORDANT 
Twenty per cent aqueous solution tannic acid. . Io cc. 
Saturated aqueous solution iron sulphate . . . 5 ¢cC. 
Saturated alcoholic solution basic fuchsin . 5 Tuee. 
Mix, let stand 2 or 3 hours, and filter. 
Tannic acid solution should be freshly prepared, but the 
iron sulphate solution is better if it stands until it begins to turn 
brownish by oxidation, but it should not be too old: If, when 
this mordant is used, it gives a precipitate, filter again. When 
properly prepared it should have much the same color as a 
solution of hematoxylin. 
LOEFFLER’S STAIN (ZIEHL’S CARBOL FUCHSIN) 
Saturated alcoholic solution basic fuchsin . . . 30c¢. 
Five per cent carbolicacid . . . . . . . . 20€C¢. 
If not clear, add fuchsin solution drop by drop until it clears, 
then filter. 
PITFIELD’S MORDANT 
Ten per cent aqueous solution tannic acid . . . Iocc. 
Saturated aqueous solution mercuric chloride 5 ce. 
Saturated aqueous solution potassium alum . . 5c. 
Ziehl’s carbol fuchsin . . . a ee GHC 
Mix, let stand 2 or more hours, and decant clear fluid or 
filter. 
PITFIELD’S STAIN 
Saturated aqueous solution potassium alum . . Iocc. 
Saturated alcoholic solution gentian violet. . . 2 ce. 
Mix, let stand 2 or more hours, and filter. 
