Another point to be remembered in all cases of disinfection by formaldehyde is that a mechanical cleansing must precede the action of the antiseptic. If there are thick deposits of organic matter which can be easily dislodged with a scrubbing brush, they can only be disinfected by the use of large quantities of formaldehyde used during a long period of time.

General Disinfectants.—
I.—Alum10 ounces
Sodium carbonate10 ounces
Ammonium chloride 2 ounces
Zinc chloride 1 ounce
Sodium chloride 2 ounces
Hydrochloric acid, quantity sufficient.
Water to make 1 gallon.

Dissolve the alum in one half gallon of boiling water, and add the sodium carbonate; then add hydrochloric acid until the precipitate formed is dissolved. Dissolve the other salt in water and add to the previous solution. Finally add enough water to make the whole measure 1 gallon, and filter.

In use, this is diluted with 7 parts of water.

II.—For the Sick Room.—In using this ventilate frequently: Guaiac, 10 parts; eucalyptol, 8 parts; phenol, 6 parts; menthol, 4 parts; thymol, 2 parts; oil of cloves, 1 part; alcohol of 90 per cent, 170 parts.

Atomizer Liquid for Sick Rooms.—

by weight
III.—Eucalyptol 10 parts
Thyme oil  5 parts
Lemon oil  5 parts
Lavender oil  5 parts
Spirit, 90 per cent110 parts

To a pint of water a teaspoonful for evaporation.

Non-Poisonous Sheep Dips.—Paste.—