HOME ECONOMICS AND EDUCATION 665 



It can be used freely in the finest rooms as it is non-corrosive and 

 does not injure pictures, clothing or even -the most delicate fabrics. 

 It is also a true deodorizer, uniting with the products of decomposi- 

 tion to form new compounds which are free from odor and sterile. 

 Forjnaldehyde is sold in most drug stores and may be obtained under 

 two forms, formalin and paraform. Formalin is a solution of the 

 gas in water and should be 40 per cent strong. Paraform is sold 

 in tablets or cakes. An excellent method for disinfecting a room 

 consists in suspending a number of sheets on cords stretched from 

 wall to wall and spraying these with undiluted formalin. Not less 

 than ten ounces of formalin must be used for each 1,000 cubic feet 

 of space. A sheet will take about five ounces of formalin without 

 dripping. This method is almost useless in a cold room. It should 

 be employed only in warm weather or in a heated house. The tem- 

 perature should be above 65 degrees F. 



When permanganate of potash is mixed with formalin a violent 

 reaction takes place and formaldehyde gas is liberated rapidly, almost 

 the total amount of available gas being given off within a few min- 

 utes. It has been shown by experiment that a large quantity of gas 

 with short exposure is more efficient than a small quantity with long 

 exposure. For simplicity and efficiency this method is superior to 

 all others. 



Place the proper amount of permanganate in a suitable vessel 

 and pour the formalin over it. Ordinarily ten ounces of formalin 

 must be used for each 1,000 cubic feet of space. For every ounce 

 of formalin, one-half ounce of permanganate must be used. For 

 instance, if our room contains 1,000 cubic feet of space, we use ten 

 ounces of formalin and five of permanganate. On account of the 

 frothing which occurs, a deep vessel should be used, and not more 

 than a pint of formalin be used in a single vessel. The ordinary 

 galvanized iron or tin bucket may be used conveniently, employing 

 several if the room is large. The gas begins to come off almost im- 

 mediately, forcing the operator to leave the room at once. On ac- 

 count of the heat generated, it is well to place the buckets in shallow 

 pans containing water. The gas occasionally takes fire, hence there 

 is some danger in this method. The buckets must therefore not be 

 placed near curtains or any inflammable material, and must be 

 watched for a few minutes. If fire does not appear within the first 

 few minutes the room can be closed with safety. 



Paraform is sold in tablets, or in cakes. A common trade name 

 is solidified formaldehyde. Lamps of cheap construction are usually 

 sold with it, and some manufacturers put out a disinfectant con- 

 sisting of a cake of paraform in a tin container with a paraffin candle 

 beneath. Paraform is used by heating. It first melts, then goes off 

 as formaldehyde gas. It catches fire rather easily, burning with a 

 blue flame. It has no disinfecting power when burned. This meth- 

 od can be recommended only for small rooms, closets, etc. It is 

 cheap and easily handled. All cracks must be carefully sealed and 

 the room or closet kept shut twenty-four hours. At least two ounces 

 of paraform must be used for each 1,000 cubic feet of space. 



