Uses. The use of formaldehyde as a disinfectant has already been described (see page 114). In a tightly closed room, and kept closed for twenty-four hours, sheets wet with 150 mils of the official solution of formaldehyde is sufficient for disinfecting one thousand cubic feet of space. Hatcher and Wilbert caution that for this kind of formaldehyde disinfection to be efficient and successful, the temperature of the room must not be below 60° F. Solutions of formaldehyde may be used in full strength to destroy a wart, and to destroy such a skin infection as ringworm, especially ringworm of the legs. As soon as it begins to cause pain and burning, the part should be quickly washed with water, else a dermatitis will be caused. Weaker solutions may be applied to the skin every two or three days in various parasitic diseases. It is sometimes efficient in a 2 per cent. solution when applied every night for a short time to disagreeably smelling feet and axillæ. It tends to inhibit the sweat glands, and also destroys the disagreeable odor. Clothing and instruments may be disinfected by formaldehyde fumes, but formaldehyde solutions corrode instruments. Ten per cent. solutions of formaldehyde are efficient in disinfecting such excreta as sputum, urine and feces, provided they are subjected to these solutions for at least an hour. Paraformaldehyde (Paraformaldehydum) - Paraform occurs as a white solid or powder, which on heating liberates formaldehyde gas. It is antiseptic and irritant, and may be used as an escharotic to remove warts or other tissue. It should not be used internally. ANTISEPTICS One of the strongest antiseptics is the bichloride of mercury, and it is germicidal even in a solution of 1-25,000 or even weaker, but the strength of solution most frequently used for external antisepsis is from 1-2,000 to 1-1,000. Corrosive sublimate should not be used on instruments, and if used frequently on the hands it causes a dermatitis. When it is added to substances containing albumin, as the feces, it forms an albuminate which interferes with its germicidal efficiency. Tartaric acid prevents this reaction, and this acid is added to bichloride antiseptic tablets. The number of tablets required to make the various strengths of mercuric chloride solutions is indicated on the bottles containing them. On account of the frequency with which bichloride of mercury poisoning has occurred accidentally, the tablets are now colored blue or red and labelled "poison;" or they are made in triangular or diamond shape. Therefore there seems no excuse but the grossest kind of carelessness for mistaking these tablets for any other kind of tablets. The official tablets termed Toxitabellæ Hydrargyri Chloridi Corrosivi contain about one-half a grain each of mercuric chloride and sodium chloride. Mercuric Oxycyanide is a strong antiseptic and does not act on albumin as much as does mercuric chloride. It may also be used to sterilize instruments without corroding them. As an external antiseptic it is used in the strength of 1-5,000 to I-3,000. Schamberg, Kolmer and Raiziss1 have shown that Mercurophen (sodium oxymercuryorthonitro phenolate) is fifty times as active as mercuric chloride against the staphylococcus aureus, and it destroyed these bacteria on prolonged exposure in bouillon in a dilution of 1 part to 10 million. It was found to show many thousand times greater germicidal power against the typhoid bacillus, and to disinfect the hands in 1 part to 10,000 to 1 part to 40,000 in one minute, as compared with mercuric chloride, which required five minutes to disinfect the hands in the strength of 1 part to 5,000, and fifteen minutes in a dilution of 1 part to 10,000. This preparation was found to sterilize rubber tubing in thirty minutes in a dilution of 1 part to 100,000. It was found to sterilize the feces in thirty minutes in 1 part to 5,000. Nickle-plated instruments after twenty-four hours' exposure in 1 part to 5,000 of this mercurial salt showed no tarnishing. Macfarlan2 finds that potassium mercuric iodide is a distinct chemical entity, is a salt that is delequescent, and upon taking up water readily deposits red mercuric iodide. This salt is 1 Journal A. M. A., May 19, 1917, p. 1458. 2 Amer. Journ. Med. Sci., April, 1920, p. 586. most conveniently used in tablet form for antiseptic purposes. It is soluble in both water and alcohol. It is much less toxic than mercuric chloride, and therefore is safer for germicidal use in parts from which it could be absorbed. Macfarlan finds that 1⁄2 to 1 per cent. solutions are slightly irritating to mucous membranes, but solutions of such a strength have no irritating effect on the skin. Potassium mercuric iodide is a powerful germicide even in high dilutions, and he found that it kills many organisms after prolonged exposure, even in dilutions of I part to 80,000. This double iodide has been found efficient as a disinfectant for the skin in the strength of 1 per cent. in 70 per cent. alcohol. Phenol solutions are expensive, require for thorough germicidal purposes to be 5 per cent. in strength, are benumbing to the hands, more or less irritant, and are now rarely used. Labarraque's Solution (Liquor Soda Chlorinatæ) is efficiently germicidal and is especially valuable in removing bad odors. Dakin's solution is a chlorinated lime solution. Both it and the Daufresne's modification of it are difficult of preparation. Consequently, except in hospital service, a chlorinated solution is more readily made with the so-called "DichloramineT" tablets. The number of tablets to be dissolved in 100 mils, or in 500 mils (a pint) of water is designated on the bottle; the strength of solution for injection is generally 1 or 2 per cent. Chloramine-T (Sodium Paratoluenesulphochloramide) is a stable chlorinated soda antiseptic, and is used in 1 to 2 per cent. solutions in the same manner that Dakin's solution is used. Dichloramine-T (Paratoluenesulphodichloramide) is a little. more irritant than the chloramine-T, but it is more soluble. Various chloramine-T and dichloramine-T preparations are on the market. For disinfection of small quantities of water Dakin found most efficient and satisfactory parasulphondichloraminobenzoic acid. This substance can be obtained in tablet form ready for use under the name of "Halazone.” The official Liquor Formaldehydi, diluted one part to one or two thousand, may be used as an antiseptic wash, but even such weak solutions are irritant and soon cause irritation of the skin. The tincture of iodine painted thoroughly over the skin, provided the skin is dry and has not been recently moistened, is one of the best germicides that we possess. It seems to positively render sterile the region to which it is applied, and it is now used to sterilize the skin for surgical incisions. This is the age of using too much iodine, especially in the mouth, and the laity with a little knowledge of first aid to the injured use iodine too frequently. Many times it injures the tissues and prevents healing. Peroxide of hydrogen solutions in full strength or diluted depending entirely upon the part to be treated, are efficient antiseptics, but they should never be used in cavities or sinuses where there is any possibility of the bubbles of gas causing dissection or tearing of the tissues. The official Cresol is a mixture of cresols, and is a valuable antiseptic in 3 to 5 per cent. solutions. Iodoform is not an antiseptic and never should be considered such, although it may at times prevent germs from growing. Churchman,' after repeatedly urging the antiseptic value of gentian violet since 1912, again states that, even in high dilutions, this drug has great antiseptic value in long continued suppurations in old wounds, and, where the bacillus diphtheria was the infection, gentian violet properly applied killed the infection and caused healing. He also shows its effective antiseptic action, combined with lavage, in purulent arthritis. STERILIZATION Not to enter into the discussion of sterilization of instruments and dressings, it should be emphasized that intense dry heat, boiling water, and steam, applied for one-half hour or more, are the most efficient sterilizing means known, and make possible our present day aseptic surgery. Phenol.-Carbolic Acid.-Phenol crystals are used only for escharotic purposes. The official preparations of phenol are Glyceritum Phenolis and Phenol Liquefactum which occurs either as a colorless or slightly reddish liquid and should contain not 1 Journal A. M. A., Jan. 17, 1920, p. 145. less than 87 per cent. of phenol. The official Unguentum Phenolis contains 24 per cent. of liquefied phenol. Phenol, carbolic acid, is obtained from coal-tar by fractional distillation, but it may also be made synthetically. Neither phenol nor any of its preparations should be used internally. Action. When liquefied phenol is used in full strength, or nearly full strength, it blanches the skin and mucous membranes, causes a sharp, burning pain, soon followed by dulling of sensation. In other words, it causes localized anesthesia. It may or may not blister with one application, but the part to which it is applied turns white, and if the application is longer than momentary, the part becomes necrotic, and continued applications of even weak solutions will cause gangrene. Hence it is inexcusable to keep a part wet with phenol solutions. Except in weak solutions it is irritant to the skin and mucous membranes. In 10 per cent. solutions, applied to a part for a short period, it causes considerable anesthesia, and incision may be made through the skin in this region without pain; but other methods of producing local anesthesia for operative purposes are better. Frequent applications of even weak solutions to the skin will cause eczema, and perhaps dermatitis. On the other hand, solutions as weak as 2 per cent. may soothe an irritated and inflamed region, but if the surface is denuded of skin, dangerous absorption may occur. Other preparations for soothing the skin and stopping itching are better. Toxic Action.-When this drug is absorbed in a small amount, it is irritant to the central nervous system, causing headaches, irritability, restlessness, and muscle twitchings. The digestion is slowed, and vomiting and purging may occur. The urine becomes dark, if much of the drug has been absorbed; there is irritability of the bladder, urination becomes more frequent, and albumin may appear in the urine. Soon, if more phenol has been absorbed, the circulation and respiration are depressed. If a considerable amount has been rapidly absorbed the symptoms are those of collapse and drowsiness. The pulse becomes weak and thready, the face pale, the skin covered with clammy perspiration, and muscular twitchings occur. If the patient long survives the poisoning, there may be suppression of |