Dr. Harlan recommends the following for softened dentine: Corrosive sublimate, peroxide of hydrogen and tartaric acid combined, applied with wood or platinum points ; then dry the cavity and apply myrtol in full strength and dry it again. He also says: If it is deemed a necessity to apply an antiseptic agent to a cavity in a tooth having a living pulp, an oil (one of the essential oils, such as peppermint, camphor, turpentine, thyme, cassia, cinnamon, caraway, eugenol, cajuput, eucalyptol, terpinol, myrtol, sassafras), may be left in contact with the cavity, sealed with gutta percha, or the cavity may be stopped with oxysulphate of zinc for any number of days. The cavity should be well dried before introducing the oil. He also remarks that there is no theoretical objection to the use of carbolic acid in a living tooth, if it is reapplied from time to time perfectly warmed. It should not be used to protect the pulp from the invasion of microorganisms or deep-seated cavities, as it will prove inadequate by lack of diffusibility.

"It is a mistaken idea to suppose that an agent like carbolic acid, liquefied or diluted with water, will prove a permanent antiseptic in the presence of moisture, such as is nearly always present in a tooth. It does not possess embalming properties because it is easily absorbed and disappears. It should form no part of root-filling, nor should it be introduced into roots permanently. Copal, Canada balsam, or other agents of this class, may be used on an exposed pulp in its stead, and for injection into abscesses, using the root of the tooth as a channel, potass-permanganate, silico-fluoride of sodium, boro-glycerine, the oil of cloves, cassia, cinnamon, myrtol, and agents of this class, are far more powerful, with better stimulating, antiseptic and disinfectant properties, and they do not possess the coagulating properties of carbolic acid, or its disagreeable odor, and under no circumstances will they clog a delicate canal or destroy the soft tissue to which they are applied. Carbolic acid should take its legitimate place as a spray, a local anaesthetic and component of mouth washes in dental practice, and as an adjuvant to the oils where local medication around the roots of teeth may be indicated, or for injection into the antrum of Highmore, combined with tannin, glycerine, camphor or potash, or be relegated to the laboratory as a component of sodium phenate, or in other chemical uses."

Incompatible Antiseptics

Corrosive sublimate and iodine ; corrosive sublimate and soap; iodine and soap; carbolic acid and iodine ; carbolic acid and permanganate of potassium ; salicylic acid and soap ; salicylic acid and permanganate of potassium ; permanganate of potassium and oils, soap, or glycerine; aristol and caustic alkalies, ammonia, mercuric chloride, metallic oxides, starch, or any substance which possesses a powerful affinity for iodine.

Disinfecting Or Sterilizing Instruments, Etc

Dr. W. D. Miller, in an article on the disinfection of dental and surgical instruments, says: " There is no department of surgery in which the demand for antiseptic procedure is more urgent than in dentistry, for the reason that all of our operations are performed upon septic or infected tissues, and we have no means of rendering the territory to be operated upon aseptic except by the use of antiseptics of the highest character. We cannot extract a tooth, cleanse the canal of a pulpless tooth, excavate a cavity of decay or lance the gums; we cannot even touch any point in the oral cavity without our instruments becoming coated with a layer of infectious material. We are therefore bound to use antiseptics, not only for the purpose of disinfecting the already infected tissues, but for sterilizing our instruments to avoid the transmission of infectious matter from one patient to another." "The necessity for absolute cleanliness on the part of the dentist, of his hands as well as of his instruments, napkins, drinking-glasses, rubber-dam, in short of everything with which he comes in contact with the patient's mouth, is universally recognized; at least there can be no one who has the courage to express a contrary opinion." "We can never know what virus may be clinging to our instruments, nor can we with certainty predict the result of a wound upon the gums, cheeks or lips with an unclean instrument."

From Dr. Miller's experiments we deduct the following: Boiling napkins for 10 or 15 minutes in soap-water completely sterilizes them. Small pieces of rubber-dam can be sterilized as a rule by exposing them for 30 minutes to a five per cent. solution of carbolic acid; small and large pieces of the dam are completely sterilized by subjecting them to boiling water for from six to fifteen minutes, according to size.

Drinking or rinsing glasses can be sterilized by boiling in pure water. Concerning instruments, he says: The ideal antiseptic is a liquid which acts immediately upon bacteria without in any way injuring the instrument. His results were as follows: A five per cent. solution of carbolic acid required one hour to sterilize instruments, and even after such a time the result was not certain ; and of twenty-one pieces placed in concentrated carbolic acid for varying periods of time ranging from one to twelve minutes, only two were sterilized.

A five per cent. solution of trichlorphenol required an hour's time to sterilize. Lysol gave results nearly identical with those of trichlorphenol. An action of from fifteen to twenty minutes in a five per cent. aqueous solution of the bichloride of mercury gave the most promising result and can be relied upon to produce thorough sterilization; but he considers the time required to be so long as to render a five per cent. solution of the bichloride of mercury unsuitable for the purpose; besides the powerful action of this agent upon steel or iron is a serious objection to its use as a sterilizer. A ten per cent. solution of the peroxide of hydrogen came next to carbolic acid, but is considerably inferior to it. The essential oils in emulsion, as well as in pure form utterly failed to sterilize.

He finally concluded that boiling water is far superior to chemical antiseptics, and all other means, for sterilizing dental instruments, and that its easy application and rapid action should recommend it to every practicing dentist and physician. He regards an exposure of three minutes to boiling water sufficient for sterilizing the smaller dental instruments, and five minutes for any other. The addition of soda will prevent the rusting which is liable to occur when the instruments are boiled in water alone; hence a boiling solution of carbonate of sodium appears to be the most promising. Dr. Miller recommending an exposure of three to five minutes to a boiling one or two per cent. solution of soda for sterilizing dental and surgical instruments. The solution must not be simply hot, but boiling, since the motion of the boiling water materially assists in rapidly raising the temperature of the instruments to 100° C, and at the same time loosens up any matter that may be clinging to them. Solutions of such agents as bichloride of mercury, campho-phenique eugenol, oil of cassia, oil of turpentine, terpinol, formaldehyde gas obtained from para-form, lysol, carbolic acid, aseptol, trichlorphenol, a boiling solution of carbonate of sodium, steam, are employed for disinfecting dental instruments and appliances. Bichloride of mercury although an effective sterilizer, will injure instruments. Steam is an efficient sterilizer, and a simple method for its use is recommended by Dr. K. C. Gibson; it consists in placing the instruments in a cotton or linen bag tied closely at the top, which is put into the ordinary dental vulcanizer, and subjected to steam pressure, as shown by the thermometer, of 2300 F. for ten minutes. A small quantity of bicarbonate of soda placed in the water will prevent the instruments from rusting. (See Formaline for disinfecting instruments, etc., with formaldehyde gas.)

To Render The Hands Aseptic

Dr. Noble says: Trim the nails reasonably short, and clear the subungual spaces with the knife blade. Then thoroughly wash the hands and forearms in warm water, a good lather being made with soap, and a stiff brush vigorously applied. Renew the water three times. Next soak the hands in a saturated solution of oxalic acid. According to circumstances the finger tips are then soaked in peroxide of hydrogen. For the final bath, corrosive sublimate solution, 1 to 1000, is employed; allow the hands to remain in this solution three minutes.