The expectorants which act by increasing the activity of the expulsive apparatus may be divided into (1) Those which increase the rapidity of the ciliary motion in the tracheal mucous membrane.

(2) Those which increase the activity of the respiratory centre.

We have no direct experiments or observations on the rapidity of the ciliary motion in the bronchial mucous membrane of the higher animals, but ammonia has been found to increase its rapidity in the mucous membrane of the frog.

The remedies which increase the activity of the respiratory centre are: strychnine, ammonia, emetine, ipecacuanha, belladonna, atropine, senega, and saponine. They are used more especially in cases of bronchitis where the expectoration is imperfect.

The chief expectorants have been divided into depressant and stimulant. They are as follows :Depressant Expectorants.

Generally tending to depress the heart, lessen blood-pressure, and increase secretion.

Antimonial preparations.

Tartar emetic. Alkalies. Ipecacuanha.

Emetine. Lobelia.

Lobeline. Jaborandi.

Pilocarpine. Apomorphine. Quebracho.

Quebrachine Potassium iodide.

Stimulating Expectorants.

Generally stimulating the heart, increasing blood-pressure, and diminishing secretion. Acids.

Ammonium salts

chloride, carbonate.

hydrate (Ammonia)

Nux vomica.

Strychnine. Senega.

Saponine. Squill.

Balsams

Benzoin.

Benzoic acid.

Balsam of Tolu.

Balsam of Peru.

Terebin-thinates

Wood tar.

Terebene.

Turpentine.

Oleum Pini

Sylvestris.

Oleum Pini

Pumilionis.

Sulphur.

Sulphur oils

Onion.

Garlic.

Saccharine substances

Syrups.

Liquorice.

Adjuncts

One of the most powerful adjuncts to expectorants is an emetic, which frequently will clear the lungs and save life in cases of chronic bronchitis with impending suffocation, when ordinary expectorants have completely failed.

One of the emetics most commonly employed in such cases is ipecacuanha, either alone or combined with squill, e.g. half a fluid ounce each of ipecacuanha wine and oxymel of squills. When there is great depression, however, and the circulation is very feeble, carbonate of ammonium is to be preferred.

Another powerful adjunct is warmth and moisture in the room in which the patient is living, and this is best secured by means of steam brought well into the room from a kettle placed upon the hob. The kettle used should either be furnished with a very long spout, as in the case of the ordinary bronchitis kettle, or a long tube made of a piece of stout brown paper tied around with a string may be used to convey steam into the room from the nozzle of an ordinary kettle.

Respirators are also serviceable, by preventing the entrance of cold air into the trachea. Many persons, forgetting that the mouth is part of the digestive tract, and that the nose is the proper entrance to the respiratory tract, breathe through their mouth; the consequence is, that the cold air passes down the trachea without being previously warmed. In the nose we have a special arrangement for warming the air. The turbinated bones present an enormous warming surface, like some recently-invented stoves, and moreover, a special arrangement is made for allowing a free flow of blood through this mucous membrane by its being loosely instead of firmly attached to the turbinated bones. Its vessels are therefore capable of great and rapid distension, so as to allow the air to be readily warmed in cold weather.

Most respirators are made simply to go over the mouth, and their advantage is that they force people to breathe through their nose, or warm the air if they cannot do so, and continue to breathe through the mouth. In many persons the same end may be gained by forcing them to wear an invisible respirator. An instrument is sold bearing this name, consisting of a thin plate of metal; but what is perhaps quite as good, or better, is a sovereign or half-sovereign placed between the lips and teeth. Patients are thus forced to keep the mouth shut in order to prevent it from falling out, and its value makes them careful about losing it.

It is often forgotten too that passages and disused rooms are nearly as cold as the external air, and many delicate people who would never dream of going outside in cold weather will, without thinking, walk through cold passages and in rooms without fires. Warm clothing", especially over the shoulders, neck, and chest, is very useful, and its utility is recognised by the common employment of so-called chest protectors made of chamois leather and red flannel.

Other adjuncts are friction to the chest with stimulating liniments; mustard leaves, warm poultices and the application of plasters; the emplastrum calefaciens (B.P.) or emplastrum picis cum cantharide (U.S.P.) is especially useful in chronic bronchitis.