Note 4 — Chapter XIII

There are many formaldehyde preparations on the market, simple and easy to use, but these may be unobtainable. In this case, an effective method is the combination of formaldehyde with potassium permanganate. For a room containing 1000 cubic feet of air space (a room 10 feet long, 10 feet wide, and 10 feet high), the amount needed is: Potassium permanganate, oz. 111.; liquid formaldehyde, pint 1. Place the formaldehyde in a large galvanized iron bucket (holding 8 to 10 quarts), and drop the permanganate into it. The room should be left closed for six hours; a longer time is unnecessary, a shorter time ineffectual. All cracks, of course, should have been previously stopped.