Properties: Germicide, disinfectant, antiseptic.

Use: The 40% liquid solution is the commercial formaldehyde used in medicine; also known by the name of formalin or formal. A gaseous body produced from methyl alcohol by oxidation. It is a light green, almost white, volatile liquid. Formaldehyde gas which is generated by special apparatus made for the purpose, is our best disinfectant. It is far superior to sulphur, not discoloring or destroying the finest fabrics, books, paintings or woodwork. It will not cause iron or steel to rust, nor copper, nickel or bronze to tarnish; therefore it is a good sterilizer for surgical instruments. With a proper generator such as can be bought in the market, the gas is the best form for disinfecting rooms. This can be done by passing the gas through a tube through the keyhole, and after sufficient has entered the room, it should be kept closed for some time. No person should be in the room at the time of disinfecting nor some time after, as the gas is dangerous to animal life. It is claimed that it will cause fleas, mosquitoes, moths, etc., to die or depart if possible. Its germicidal properties are equally effective whether in form of liquid or gas. The 40% liquid solution is too irritating to the tissues of the body; but well diluted it is one of our very best antiseptics. Its power to effect chemical changes in albuminous or nitrogenous matter makes it a valuable surface disinfectant and far superior to other germicidals. As it combines readily with hydrogen sulphide and the volatile compounds of ammonia it is a valuable deodorizer; will also remove the odors of decomposing animal and vegetable matter. A 4% solution of the 40% liquid solution is a very good application in gonorrhea of the female; to be used as a swab on cotton. It destroys the gonococci and restores the parts to health. Diluted according to the requirements of the case; it is used with success in diphtheria, whooping cough, open and infected wounds, ulcers, etc. In fact it is a valuable wash and dressing. In chancroid apply 40% solution full strength and it will heal promptly. In severe cases of diphtheria full strength may be applied to the membrane. The following liquid solution of the commercial formaldehyde as used in medicine may serve as a guide to its use: 1:2500 destroys micro organism in 1 hour: 1:500 useful as a mouth wash, to irrigate, clean catheters, etc.; 1:250 useful as a spray in sick rooms, as a deodorant, for cleaning hands, instruments, etc.; 1:100 may be used in skin diseases; 1:50 will sterilize catgut, silk, etc., but a weaker solution may be used, in which case they must remain longer. Infected wounds, carbuncles, etc., a .2% solution is useful. A 1% solution may be inhaled or used as a spray in whooping cough and hay fevers. In suppuration a 25% solution is the best proportion. In packing and drainage of sinuses, pus cavities, abscesses, etc., it is superior to any other antiseptic. It answers the purpose of iodoform and is a thousand times better; does not poison the system and certainly the odor is by far more to be preferred than that of iodoform, which should be entirely dispensed with in surgery. The solutions recommended are as a rule by far too strong. A 4% solution answering in most all cases of antiseptic surgery, drainage, packing, etc. If too strong it will harden tissue and this is to be avoided unless undesirable or dead tissue is to be removed. Moist inhalations are of great value in tuberculosis of the lungs. Applied to corns, after hard epidermis is removed by salicylic acid and warm foot baths, it will dry them up. It may be applied to cancers to great advantage, serving both as a deodorizer, destroyer of cancer cells and general antiseptic. Should be applied under oiled silk. As uterine or vaginal douches the 4% solution or milder is very good treatment in inflammation of these parts and in septic conditions. Formaldehyde should not be mixed with glycerine as it impairs its value and is less harmless as a disinfectant. In this combination if used to fumigate it will injure fabric which it otherwise will not do. Where the physician is unable to have a generator for fumigation or disinfecting, formalin lamps can be used; these are reasonable in price and answer the purpose well. The fluid diluted is a good disinfectant but not as powerful or penetrating as the gas produced by generators.

The Materia Medica and Clinical Therapeutics, 1905, was written by Fred J. Petersen, M.D.