THE VENETIAN TURPENTINE METHOD 
105 
should be of the best quality; otherwise the turpentine will become 
too thick. While it can be thinned by adding thin turpentine, it is 
better, for easy mounting, not to let the turpentine become too thick. 
If the turpentine is only a little too thick, warming it gently will 
thin it enough for making mounts; but if any material is to be put 
away, a few drops of absolute alcohol or of a thin Venetian turpentine 
should be added. Material in Venetian turpentine, well corked 
and kept in the dark, does not fade or deteriorate in any way. 
Magdala Red and Anilin Blue.—Fix in chromo-acetic acid and 
wash in water, as described in the previous schedule. Transfer 
from water to 10 per cent glycerin and allow the glycerin to con¬ 
centrate. It is not necessary to use an exsiccator since there is no 
danger from moisture in the air. When the glycerin attains the 
consistency of pure glycerin, wash the glycerin out with 95 per cent 
alcohol and then proceed with the staining. 
1. Stain in Magdala red. At least two Magdala reds are sold 
by dealers. The one marked “echt” is more expensive, but, in our 
experience, is inferior to the one marked simply “Magdala red.” 
Make a 1 per cent solution in 90 per cent alcohol. We use the stain 
much stronger than recommended by Pfeiffer and Wellheim. The 
pure stain, allowed to act for 24 hours, does not stain too deeply. 
2. Rinse the material for a minute in 90 per cent alcohol. 
3. Stain in anilin blue, using a 1 per cent solution in 90 per cent 
alcohol. We prefer to make a fresh solution every time we have 
anything to stain. It is not necessary to measure it. A little of the 
powder—about half the bulk of a grain of wheat—in 30 c.c. of 90 
per cent alcohol, will give an efficient solution. The time required 
for successful staining will vary from 3 to 30 minutes. Do not put 
all the material into the anilin blue at once, but, by trying a few 
filaments at a time, find out what the probable periods may be. 
4. Rinse off the stain in 90 per cent alcohol, and then treat for a 
few seconds in acid alcohol (1 very small drop of HC1 to 30 c.c. of 90 
per cent alcohol). The acid alcohol fixes and brightens the anilin 
blue, but extracts the Magdala red. If the anilin blue or the acid 
alcohol acts for too short a time, the blue will be weak; if they act 
too long, the red is lost entirely. If the blue overstains too much, 
wash it out in 95 per cent alcohol. If the red overstains, wait until 
the mount is finished, and then reduce the red by exposing the slide 
to direct sunlight. 
