Definition. - A liquid composed of not less than 86.4 per cent., by weight, of absolute phenol and about 13.6 per cent., by weight, of water.

It is prepared from phenol (Acidum Carbohcum, U. S. P., 1890) by the addition of distilled water in the proportion of 1 Gm. of the latter to 9 Gm. of phenol. Introduced on account of the ease of dispensing.

Dose. - Average dose: 1 minim (0.05 Cc). U. S. P.

Physiological Action.- Externally. - Carbolic acid destroys micro-organisms. Spore-bearing forms are very resistant to its action. Two per cent. solutions are effective for many bacteria, but they are not always efficient as germicides. Phenol is a local anesthetic, and, applied in full stength to animal tissues, acts as a caustic, but does not produce vesication. In weaker solutions it produces a burning and reddening of the skin. It acts more severely upon mucous membranes. It coagulates albumin, and therefore its caustic action is limited.

The eschar is first whitish, subsequently becoming brownish. It is readily absorbed through the skin or through raw surfaces, and toxic effects have been thus produced. Weak solutions, 2.5 per cent., in contact with an area, such as a finger, may cause gangrene of the parts.

Internally. - Digestive System. - In small doses it is anesthetic and sedative to the stomach. In large or poisonous doses it is a powerful gastro-intestinal irritant. Ordinary medicinal doses are converted by the gastric contents into the sulphocarbolates.

Circulatory System. - Medicinal doses have no apparent effect on the circulation. Large doses first depress, and later accelerate, the heart. Poisonous doses powerfully depress the heart, stopping it in diastole. The arterial tension is lowered by lethal doses.

Nervous System. - Medicinal doses have no special effect upon the nervous system. Large or poisonous doses depress the cerebrum. Vertigo may first be noticed, which is soon followed by stupor. There may be muscular trembling or convulsions.

Respiratory System. - Small doses do not affect the respiration. Large doses first accelerate the respiratory movements, rendering them full, but shallow respirations soon follow. This action is due to stimulation of the vagi, both at the periphery and of the center. If the dose has been a poisonous one, there is great depression, and ultimately paralysis of respiration due to depression of the centers.

Absorption. - It is absorbed from the stomach, and diffuses into the blood with great facility, circulating in that tissue probably as an alkaline carbolate.

Elimination. - It is eliminated by all the secretions - chiefly by the kidneys and lungs - and appears in the urine as salts of sulpho-carbolic and glycuronic acids, and to oxidated products of the dioxybenzoles, hydrochinon and pyrocatechin. To the latter substances, after further oxidation, mainly is due the peculiar smoky or olive-green color imparted to the urine after large or continued doses have been taken. Much of the phenol is eliminated unchanged.

Temperature. - It is not specially affected by small doses. Full medicinal doses tend to lower bodily temperature in fever, while poisonous doses lower the temperature several degrees. The reduction of temperature is due to its diminishing heat-production and increasing heat-dissipation.

Eye. - Poisonous doses almost invariably cause the pupil to be minutely contracted, due, probably, to paralysis of the radiating fibers, the circular fibers being unaffected.

Untoward Action. - Headache, either in the frontal or the occipital region, heaviness and a sensation of fulness in the head, dizziness, and the appearance of rings before the eyes, muscular weakness, especially of the legs, profuse sweating, and extensive formication.

Where there is an idiosyncrasy on the part of the individual against this drug, small doses even may produce the symptoms of poisoning.

Poisoning. - Carbolic acid is one of the most widely used poisons. 8.5 Gm. has caused the death of an adult in fifteen minutes. 3 Gm. in solution thrown into the pleura has caused dangerous symptoms. .13 Gm. rubbed on the skin has caused death. 1.5 Gm. has caused the death of a child after a short time.

The patient is rendered rapidly unconscious or may drop dead in twelve to fifteen minutes after taking from respiratory paralysis. Should the dose be insufficient to produce so sudden a death, the patient suffers from all the symptoms of gastro-enteritis - intense pain, with violent vomiting of white slimy mucus and purging. Fibrillary trembling may be present. Stertorous breathing appears, with cold, clammy skin, pinched face, anxious expression, abolition of reflexes, weak, thready, and often imperceptible pulse, feeble respiration, and frequently dyspnea, and death finally occurs from failure of respiration.

Salivation is a common symptom of carbolic-acid poisoning. The characteristic burn of the lips is whitish. The odor is an important diagnostic sign.

As toxic symptoms may be produced by the external application of solutions of carbolic acid, as in surgical dressings or vaginal or intrauterine douches, the toxicity of this drug should be appreciated, and patients carefully watched for the first untoward manifestations, such as pain in the lumbar region, smoky urine, nervousness, and cerebral disturbance, small pulse, depressed temperature, hot and cold flashes, etc., when the drug should be immediately withdrawn.

Treatment of Poisoning. - The immediate and frequent washing out of the stomach with administration of magnesium sulphate (Epsom salts), sugar and lime solution (lime water, sugar 3, and water 12), and warm demulcent drinks should be resorted to. The application of external heat. Atropine and strychnine hypodermically. Digitalis and coffee may also be required. Opium, or some preparation of it, for the relief of pain.

Alcohol is an efficient antidote if promptly given. Locally applied, it prevents the caustic action of even pure phenol.

Therapeutics. - Externally and Locally. - For some time after it was so prominently brought forward by Lister carbolic acid was thought to be indispensable in antiseptic surgery. It is now known that the solutions which are safe to use are inefficient, ordinarily, beyond the mere mechanical effect of washing.

The benumbing influence produced on the hands of the surgeon, and the discoloration of bright instruments and rapid impairment of their cutting surfaces, render strong solutions for disinfecting instruments impracticable, and, indeed, of less value for this purpose than the prolonged boiling in distilled water rendered slightly alkaline with sodium bicarbonate.

The pain of superficial burns is relieved by applying strong solutions of carbolic acid, care being taken to prevent absorption.

It is an extremely valuable drug as an antipruritic, and is hence of great utility in the treatment of certain diseases of the skin - pruritus, chronic eczema. In chilblains, tinea tonsurans, tinea capitis, taenia circinata, favus, etc., it is of value. Chronic laryngitis, characterized by diminished secretion, is greatly benefited by the direct application to the parts of a solution of 1/2 dram to I ounce of glycerin (2.0-30.0 Cc). A spray containing from 2 to 5 grains (0.12-0.36 Gm.) to 1 ounce (30.0 Cc.) of water is an efficient application in the treatment of acute and chronic inflammation of the throat and nose.

As a deodorant it is valuable to correct the fetor arising from syphilitic ulcerations, carcinoma, gangrene of the lungs, bronchor-rhea, pneumothorax, etc.

It reduces the discharge and relieves the pain in acute otitis media: a 10 per cent. solution in glycerin should be used. It is also of value in the treatment of otorrhea and in acute perforations of the tympanic membrane, but should be used in much weaker solutions - 1 or 2 per cent.

A lotion, 8 to 15 grains (0.5-1.0 Gm.) to 1 ounce (30.0 Cc), is an efficient antiseptic in foul and indolent ulcers.

The pure acid is used as a cauterant in chancroids, lupus, gangrene, bites of rabid animals, etc.

The iodized carbolic acid is a valued local remedy in endometri' tis, chronic endocervicitis, and ulcers of the cervix.

Crude carbolic acid is useful as a disinfectant.

Internally. - While inferior to salicylic acid to check fermentation, it is nevertheless used for that purpose in dilatation of the stomach and so-called fermentative, ox flatulent, dyspepsia.

In nervous and irritative vomiting it may be given in doses of from 1 to 2 minims (0.06-0.12 Cc), well diluted and repeated at intervals of from one to four hours according to the symptoms of the case.

It has been used in acute and chronic dysentery, and as an anthelmintic against ascarides and tcenia solium.

It has also been advocated as a remedy for typhoid fever and in malarial cachexia, but purely upon hypothetical grounds, no clinical results having thus far justified its use in these disorders.

Administration. - It may be given internally in pills or capsules, mixed with powdered licorice-root as an excipient, or dissolved in glycerin and well diluted with sweetened water.

For external use various strengths are used (from 1: 10 to 1: 500), and the various preparations mentioned may be used according to the case and indications. It is to be noted that a strength above 1: 10 is liable to produce vesication, and that even in 2 per cent. solutions it has caused gangrene of the part to which it has for some time been applied.