Carbolic acid is very irritant to tissues, and carbolized dressings may be responsible for sloughing of the wound. Because of its irritant properties wounds which have been irrigated with it should be well drained. Carbolic acid, like corrosive sublimate, is inert in fatty tissues. Carbolic acid is readily absorbed, and may thus produce toxic symptoms. Absorption is not uncommon when the weaker solutions are used, but rarely occurs when a wound has been brushed over with pure acid, because the pure acid at once forms an extensive zone of coagulation, which acts as a barrier to absorption. One of the early indications of the absorption of carbolic acid is the assumption by the urine of a smoky, greenish or blackish hue. Examination of such smoky urine shows a great diminution or entire absence of sulphates when the acidulated urine is heated with chlorid of barium. This diminution of precipitable sulphates is explained by the fact that these salts are combined with carbolic acid, forming soluble sulphocarbolates (Griffin). Such urine is apt to contain albumin. If during the use of carbolized dressing or the employment of carbolic solutions the urine becomes smoky, the use of the drug in any form must be at once discontinued, otherwise dangerous symptoms will soon appear. These symptoms are subnormal temperature, feeble pulse and respiration, muscular weakness, and vertigo. If death occurs, it is due, as a rule, to respiratory failure. The treatment of slow poisoning by carbolic acid consists in at once withdrawing the drug, giving stimulants and nourishing food, and administering sulphate of sodium several times a day and atropin in the morning and evening.

Pure carbolic acid is a reliable disinfectant for certain conditions. It is used to destroy chancroids, to purify infected areas, to disinfect the medullary cavity in osteomyelitis, to stimulate granulation after the open operation for hydrocele, or to purify sloughing burns. The pure acid will not produce constitutional symptoms, but it occasionally causes sloughing. Its application causes pain for a moment only, and then analgesia ensues. Even dilute solutions of carbolic acid greatly relieve pain when applied to raw surfaces.

Carbolic acid is certainly fatal to but few bacteria and it fails to kill most spores. It acts more slowly and less certainly than corrosive sublimate. It requires 24 hours for a 5 per cent. solution to kill anthrax-spores. Pus or blood (albuminous matter) greatly weakens the germicidal power of carbolic acid, and fatty tissue cannot be disinfected by it. It is not even the best of agents in which to place instru

ments, as it dulls them. After operation upon the mouth it is used as a wash or gargle, I to 2 per cent. being a suitable strength. It is used sometimes to irrigate the bladder and often to cleanse sinuses, but is not employed in the peritoneal cavity or the brain. It is occasionally injected into tuberculous joints.

Kreolin, which is a preparation made from coal-tar, is a germicide without irritant or toxic effects. It is less powerful than carbolic acid but acts similarly, and is used in emulsion of a strength of from 1 to 5 per cent., and does not irritate the skin like carbolic acid.

Peroxid of hydrogen is a most admirable agent for the destruction of pus cocci. It comes in a 15-volume solution, which is diluted one-half or two-thirds. It probably destroys the albuminous element upon which bacteria live, and starves the fungi. The peroxide of hydrogen is not fatal to tetanus bacilli. Some surgeons use it to wash out appendicular abscesses. It must not be injected into an abscess unless a large opening exists, as otherwise the evolved gas may tear apart structures and dissect up the cellular tissue. In a deep abscess of the neck the author saw this agent almost produce suffocation, the gas passing under the mucous membrane and nearly blocking the air-passages.

Iodoform is largely used; it is not truly a germicide, as bacteria will grow upon it, but it hinders the development of bacteria and directly antagonizes the toxic products of germ-life. It can be rendered sterile by washing with a solution of corrosive sublimate. It is of the greatest value when applied to infected areas and tuberculous processes. Clinically, no real substitute for it has yet been found. It need not be applied to clean wounds, but the powder is very useful when dusted in infected wounds. It prevents wound-discharges from decomposing and greatly allays pain. Gauze impregnated with iodoform is used to drain abscesses, to drain the belly under certain circumstances, to pack aside the intestines and prevent their infection during some abdominal operations, and as packing to arrest intracranial hemorrhage. Tuberculous joints and cold abscesses are injected with iodoform emulsion, which is made by adding the drug to glycerin or olive oil. The strength of the emulsion is 10 per cent. A solution in ether of a strength of 10 per cent. may be used to inject the cavity of a cold abscess.

The drug must be used with some caution. Absorption from a wound sometimes happens, producing toxic symptoms. These symptoms are frequently misinterpreted, being usually

attributed to infection. The symptoms in some cases are acute and arise suddenly, and consist of a hallucinatory delirium, nausea, fever, watery eyes, contracted pupils, metallic taste in mouth, yellowness of the skin and eyes, an odor of iodoform upon the breadth, the presence of the drug in the urine, the outbreak of a skin eruption resembling measles, and excessive loss of flesh and strength. Patients with such acute symptoms usually pass into coma and die within a week. Such attacks are most apt to arise in those beyond middle life (see Gerster and Lilienthal, in Foster's Practical Therapeutics). In some chronic cases, the first symptoms observed are moroseness, bewilderment, and irritability, followed by depression with unsystematized persecutory delusions, delirium, coma, and even death.

In systemic poisoning by iodoform, stop the use of the drug and sustain the strength of the patient while nature is removing the poison.

Iodoform sometimes produces great local irritation of the cutaneous surface, shown by crops of vesicles filled with turbid yellow serum or even bloody serum. These vesicles rupture and expose a raw oozing surface, looking not unlike a burn. The use of the drug must be at once abandoned, for to continue it will not only increase the dermatitis, but will produce constitutional symptoms. Wash the vesiculated area with ether to remove iodoform, open each vesicle and dress the part for several days with gauze wet with normal salt solution. After acute inflammation ceases apply zinc ointment or cosmolin.

Europhen is a powder containing iodin, and the iodin. separates from it slowly when the powder is applied to wounds or ulcers. It does not produce toxic symptoms readily, if at all, and is a valuable substitute for iodoform. It is used especially in the treatment of ulcers and burns.

Nosophen is a pale yellow powder containing 60 per cent. of iodin. Its bismuth salt is known as antinosin. Nosophen is not toxic, is free from odor, and is the best of the substitutes for iodoform.

Acetanilid is frequently used as a substitute for iodoform. It is of value when applied to suppurating, ulcerating, or sloughing areas, but it does not benefit tubercular conditions. Sometimes absorption takes place to a sufficient extent to cause cyanosis. If cyanosis arises, stop the drug and order. stimulants by the stomach.

Silver is a valuable antiseptic. Halsted and Bolton have shown that metallic silver exerts an inhibitive action upon

the growth of micro-organisms and does not irritate the tissues. Credé has demonstrated the same facts. These statements indicate one great reason why silver wire is so useful as a suture-material. Halsted is accustomed to place silver foil over wounds after the wounds have been sutured, and Credé employs as a dressing a fabric in which metallic silver is intimately incorporated.

Credé considers that silver lactate (actol) is an admirable antiseptic. It does not form insoluble albuminates when introduced into the tissues and is not an irritant. Silver citrate (itrol) is said to be even a better preparation than silver lactate, and it is a useful dusting-powder.

Formaldehyd or formic aldehyd has valuable antiseptic properties. Formalin is a 40 per cent. solution of the gas in water. Solutions of this strength are very irritant to the tissues, but 2 per cent. solutions can be used to disinfect wounds. The stronger solutions are valuable for asepticizing chancroids and other ulcers. The vapor of formalin is used to disinfect wounds, and Wood suggests its employment in septic peritonitis as a means of disinfection after the abdomen has been opened. A 2 per cent. solution disinfects instruments satisfactorily.

Formalin-gelatin has recently been introduced by Schleich as an antiseptic powder. When applied to a clean wound it gives off formalin and keeps the wound aseptic. When it is applied to a sloughing surface it will not give off formalin unless it is mixed with pepsin and hydrochloric acid. The commercial preparation is known as glutol. Formalin-gelatin is used to replace bone-defects.

Nucleins, especially protonuclein, possess germicidal powers. Protonuclein is of value in treating areas of infection, particularly when sloughing exists.

Among other antiseptics of more or less value we may mention trichlorid of iodin, iodol, chlorid of zinc, chlorid of iron, loretin, salol, oxycyanid of mercury, fluorid of sodium, argonin, sugar, mustard, lannaiol, bichlorid of palladium (in very dilute solution), thymol, potash soap, iodin, salicylic acid, boric acid, camphor, eucalyptol, cinnamon, bromin, chlorin (as gas or as chlorin-water), cinnamic acid, permanganate of potassium or of calcium, chlorate of potassium, alcohol, and normal salt solution.

The best germicide is heat, and the best form in which to apply heat is by means of boiling water (even better than steam). One can use boiling water upon instruments and dressings, but rarely upon a patient and never upon the sur

geon.

Jeannel, of Toulouse, uses boiling salt solution in abscess-cavities, and other surgeons employ steam or boiling water to disinfect the medullary canal in osteomyelitis. Nevertheless, boiling water is rarely applied to the patient, and in many cases a chemical germicide must be used. The surgeon should always scrub his hands in a germicidal solution, and corrosive sublimate is one of the best we possess.

Distribution.-Microbes are very widely distributed in nature. They are found in all water except that which comes from very deep springs; in all soil to the depth of 3 feet; and in air, except that of the desert, that over the open sea, and that of lofty mountains.

Microbes may be useful. Some of them are scavengers, and clean the surface of the earth of its dead by the process known as "putrefaction," in which complex organic matter is reduced to harmless gases and to a mineral condition. The gases are taken up from the air by vegetables, and the mineral matter is dissolved in rain-water and passes into the soil from which it came, to there again be food for plants, which plants will become food for animals. Other organisms purify rivers; others cause bread to rise; still others give rise to fermentation in liquors. Microbes may be harmful. They may poison rivers and soils; they may be parasites on vegetable life; they cause diseases of the growing vine, and also of wine; they produce the mould on stale damp bread; they occasionally form poisonous matter in sausages, in ice-cream, and in canned goods; and they produce many diseases among men and the lower animals.

With so universal a distribution of these fungi, man must constantly take them into his organism. They are upon the surface of his body, he inhales them with every breath, and he swallows them with his food and drink. Most of them, fortunately, are entirely harmless; others cannot act on the living tissues; but some are virulent, and these are generally destroyed by the cells of the human body. The alimentary canal always contains bacteria of putrefaction, which act only upon the dead food, and not upon the living body; but when man dies these organisms at once attack the tissues, and post-mortem putrefaction begins in the abdomen.

Koch's Circuit.-To prove that a microbe is the cause of a disease it must fulfil Koch's circuit. It must always be found associated with the disease; it must be capable of forming pure cultures outside the body; these cultures must be capable of reproducing the disease; and the microbe