(6) Squill

(7) Turpentine.

(8) Terebene.

(9) Camphor.

(10) Benzoin.

(11) Balsam of Peru.

(12) " " Tolu.

(13) Antimony salts.

(14) Sulphur.

(15) Iodine.

(16) Tobacco.

(17) Pilocarpus.

(18) Many volatile oils.

It is probable that volatile oils and substances containing them decrease the amount of bronchial secretion as a later effect.

{6) Those decreasing it:

(1) Acids.

(2) Belladonna.

(3) Stramonium.

(4) Hyoscyamus.

Many authorities think that under some circumstances alkalies decrease the secretion.

(c) Those disinfecting it: - Drugs which, when inhaled, act in this way have already been mentioned. Copaiba, cubeb, eucalyptus, and many volatile oils are excreted partly by the bronchial mucous membrane, and thus will disinfect the secretion.

Therapeutics

In bronchitis, remedies which increase the secretion are used when it is so viscid that it sticks to the tubes and cannot be coughed up; and those which decrease it are employed when it is too watery to be easily expectorated. The use of the disinfectants is obvious.

D. Drugs relaxing spasm of the Muscular Coat of the Bronchial Tubes, or Antispasmodics. - It is believed that the symptom asthma is due to a spasmodic contraction of the bronchial tubes, and as -

(1) Stramonium.

(2) Belladonna.

(3) Hyoscyamus.

(4) Grindelia.

(5) Aspidosperma. relieve this symptom, it is concluded that these drugs relax spasm of the muscular coat of the bronchial tubes. Stramonium is the most powerful. It is very likely, judging by their analogous action in other parts of the body, that the following drugs act in the same way:

Chloroform, ether, opium, chloral hydrate, cannabis indica, amyl nitrite, and conium.

Therapeutics

Stramonium is of great use for relief of the symptom asthma, and this and the other drugs may be employed for cases of bronchitis in which it is probable that the irritation caused by the inflammation of the tubes sets up spasm of them. Many of these muscular depressants in all probability depress the nerves at the same time.

E. Drugs acting on the Vessels of the Bronchi.- These are the same as have been already described (p. 56) as acting on the vascular system generally,

F. Expectorants. - The modes of action of drugs acting on the respiratory system are so complex that it is usual to regard most of them clinically, simply as drugs which hinder or aid the expectoration of the contents of the bronchial tubes. Those which aid it are divided into two groups, named after their action, not on the lungs, but on the circulation.

I. Stimulating expectorants. - These are stimulants to the circulation generally. They are -

(1) Acids.

(2) Ammonium salts.

(3) Cocillana.

(4) Senega.

(5) Squill.

(6) Benzoin.

(7) Benzoic acid.

(8) Balsam of Tolu.

(9) Balsam of Peru.

(10) Turpentine preparations.

(11) Terebene.

(12) Oleum Pini Sylvestris.

(13) Nux Vomica.

(14) Sulphur.

(15) Quillaja.

2. Depressing expectorants. - These depress the general circulation. They are -

(1) Alkalies.

(2) Antimony salts.

(3) Ipecacuanha.

(4) Lobelia.

(5) Pilocarpus.

(6) Apomorphine.

(7) Potassium Iodide.

Therapeutics

It is almost impossible to lay down any general directions. The prescriber must consider in any case before him whether he wishes to stimulate or to depress the circulation, to increase or to diminish or to disinfect the expectoration, to stimulate the respiratory centre, to overcome spasm of the bronchial tubes, or to allay a hacking cough; and he must combine his remedies according to the answer he makes to these questions. Warmth to the chest and warm drinks are sedative, and increase the amount of secretion. Cold and cold drinks have an opposite effect.

G. Drugs which in Man sometimes produce Cheyne-Stokes Breathing. - These are morphine, potassium bromide, and chloral hydrate. In animals the following in addition may do it: picrotoxin, muscarine, digitalin, strychnine and ammonium carbonate.