This substance is used in a solution of royal blue or purple color, which should be freshly made. Place a few crystals in a piece of sterile gauze, and suspend in sterile water of the required quantity and temperature until the right color is obtained.
IODIN SOLUTION.
This solution is made by adding to sterile water of the required temperature sufficient tincture of iodin to make the color of sherry wine. Add the iodin a few drops at a time, stirring until the sherry color is produced.
SOLUTIONS OF FORMALDEHYD.
All the preparations on the market (formalin, formol, formolose, etc.) contain 40 per cent. of formaldehyd gas.
As the gas is the true germicidal principle, it is much the better plan, in stating the strength of dilute solutions of these preparations, to give the proportion of the gas present, and this is done in the formulæ below.
1 : 100 or 1 per cent. of True Formaldehyd Gas.
| Solution of formaldehyd, | fʒvj (23 c.c.); |
| Cold sterile water, | Oij (1000 c.c.). |
| This solution is approximately equivalent to | |
1 : 500 or ⅕ per cent. Solution of Formaldehyd.
| Solution of formaldehyd, | ♏︎xxxviij (2.3 c.c.); |
| Cold sterile water, | Oj (500 c.c.) |