Pixol. - A compound of tar soap and caustic potash or soda. Used as a disinfectant and antiseptic.

Pix Betulae - Picis Betulae - Birch Tar (Oleum Rusci). - Origin. - Prepared in Russia from the wood and bark of Betula alba L.

Description and Properties. - Resembling wood-tar in appearance, but remaining liquid, and having the peculiar penetrating odor of Russia leather, in the manufacture of which it is used. For the most part employed externally.

Oleum Cadinum - Olei Cadini - Oil of Cade (U. S. P.). - Origin. - A product of the dry distillation of the wood of Juniperus Oxycedrus L.

Description and Properties. - An empyreumatic, brownish or dark-brown, clear, thick liquid, possessing a tarry odor and an empyreumatic, burning, somewhat bitter taste. Almost insoluble in water; partially soluble in alcohol.

Dose. - 2-6 minims (0.12-0.3 Cc). Chiefly used externally.

Antagonists and Incompatibles. - There are none of special importance.

Synergists. - The aromatics, carbolic acid, creasote, and many of the antiseptics, turpentine, and the stimulant expectorants.

Physiological Action. - Externally and Locally. - Tar is a stimulant, astringent, antipruritic, antiseptic, and parasiticide. It is readily absorbed from the skin, and when applied too freely may produce a papular eruption.

Internally. - The action of tar closely resembles that of turpentine, although creosote is perhaps a more perfect analogue. Small doses stimulate the circulation and increase secretions generally. Immoderate dosage or the prolonged administration of tar impairs the appetite, deranges digestion, and depresses the circulatory and nervous systems.

While the drug is not considered poisonous, the ingestion of excessive quantities of oil of tar has been attended with fatal results.

The symptoms following imprudent dosage are nausea, vomiting, severe abdominal pain, diarrhea, headache, and dizziness. The urine is colored blackish-brown, and may contain blood or albumin and emit the peculiar odor of tar. There may be present erythema, or the skin may be covered with papules or vesicles attended with intense itching.

Therapeutics. - Externally and Locally. - With the possible exception of sulphur and mercury, tar is the most universally employed remedy for cutaneous diseases, the drug having for centuries held an important place among the efficient topical agents in the treatment of diseases of the skin, unhealthy ulcers, fissured nipples, boils, excoriations, etc.

In chronic eczema the drug is peculiarly servicable, and it has proved beneficial in chronic psoriasis and scabies.

The oil of cade and oil of birch are used for the same purposes as tar, being preferred by some expert dermatologists. The tarry preparations are valuable antipruritics, and of service in pruritus and various itching diseases of the skin, although their tendency to produce irritative and inflammatory effects when continuously and injudiciously applied should not be overlooked.

The benign and emollient effects of tar are best obtained when the drug is mixed with some soothing or astringent powder, such as chalk.

The valuable properties of tar in the treatment of cutaneous diseases are often nullified by the ignorance of the physician and lack of proper administration of the drug. Prof. James Nevins Hyde has truthfully observed that "the skill of a physician entrusted with the management of a disease of the skin might also be measured by his success in the use of tar."

Lozenges containing tar, the vapor of oil of tar, and sprays containing tar are extensively employed in the treatment of various diseases of the nose and throat.

Internally. - Tar has long possessed an enviable reputation as a remedy for chronic pulmonary complaints, being very efficient in the treatment of chronic bronchitis and the advanced stages of obstinate acute bronchitis, lessening the expectoration, allaying the oppression and distress in the chest, and soothing the cough. These symptoms, which attend many cases of pulmonary phthisis, are frequently relieved by some preparation of tar.

Not only is this remedy of value in catarrhal conditions of the respiratory passages; it is equally efficient in similar conditions of mucous membranes elsewhere. Thus tar water has been employed with great benefit in gleet, leukorrhea, vesical catarrh, etc., being given both by the mouth and in the form of an injection.

Administration. - Tar may be given in milk or beer or in pill form, although the most palatable forms are the syrup, glycerite, wine, and tar water, the last of which may be given to the extent of 1 or 2 pints (473.17 or 946.35 Cc.) daily.