FORMULAS FOR REAGENTS 
331 
off the end of the tube, and drop both tube and acid into the distilled 
water, or simply drop the tube into the bottle and shake the bottle 
until the tube breaks. 
Osmic Acid.— 
Five or six drops of the stock solution to 50 c.c. of water is good for 
unicellular and colonial algae. In many cases 1 or 2 c.c. to 100 c.c. of water 
is better. 
STAINS 
Delafield’s Haematoxylin.— 
To 100 c.c. of a saturated solution of ammonia alum add, drop by drop, 
a solution of 1 g. of haematoxylin dissolved in 6 c.c. of absolute alcohol. 
Expose to air and light for one week. Filter. Add 25 c.c. of glycerin and 
25 c.c. of methyl alcohol. Allow to stand until the color is sufficiently dark. 
Filter and keep in a tightly stoppered bottle. 1 
The solution should stand for at least 2 months before it is ready 
for using. 
Erlich’s Haematoxylin.— 
Distilled water. 50 c.c. 
Absolute alcohol. 50 c.c. 
Glycerin. 50 c.c. 
Glacial acetic acid. 5 c.c. 
Haematoxylin. 1 g- 
Alum in excess. 
Keep it in a dark place until the color becomes a deep red. If 
well stoppered, it will keep indefinitely. 
Boehmer’s Haematoxylin.— 
f Haematoxylin. 1 g- 
\ Absolute alcohol. 12 c.c. 
f Alum. 1 g- 
\ Distilled water. 240 c.c. 
The solution A must ripen for 2 months. When wanted for 
use, add about 10 drops of A to 10 c.c. of B. Stain 10 to 20 minutes. 
Wash in water and proceed as usual. 
Mayer’s Haem-Alum. —Haematoxylin, 1 g., dissolved with heat 
in 50 c.c. of 95 per cent alcohol and added to a solution of 50 g. of 
i Stirling and Lee. 
