It relieves cough, and is best given in the form of linctus, so as to act locally as well as generally (p. 249 et seq.). Applied locally it is used to relieve cough and pain on swallowing in tubercular disease of larynx, and a very good method is to mix 1/6 to 1/3 gr. of morphine with 1 gr. of starch or 3 grs. of subnitrate of bismuth, and blow the mixture well down into the larynx, the patient taking a deep inspiration at the same time (vide p. 497). Opium is used in asthma and bronchitis, but one should be careful of its use when the secretion from the bronchial mucous membrane is profuse; for during sleep, when the respiratory and other centres are dulled by the opium, the fluid may increase to such an extent as to suffocate the patient, who is unable to expectorate it on awaking.

Circulatory System. - It is useful in cardiac dyspnoea with sleeplessness, and in angina pectoris it sometimes gives relief.

It is useful in haemorrhages, especially those from the uterus. It may be combined with digitalis (tincturae opii m xxx., tincturae digitalis, m xxx.).

Genito-Urinary Tract. - Opium is used in diabetes to lessen the amount of urine and of sugar, but codeine (1/2-5 grs. ter die) is often used instead, the advantage it possesses being that it does not render the patient so drowsy. Opium allays irritability and pain, as in renal colic or irritable bladder.

Skin. - If the skin is too dry, Dover's powder will cause diaphoresis, and yet it will check the night-sweats of phthisis.

For the probable cause of this peculiar action vide p. 443.

The two most important uses of opium and morphine are to relieve pain and produce sleep. In their power to relieve pain opium and morphine stand unrivalled, for they can be more generally applied than anaesthetics, such as chloroform. They frequently relieve pain even in doses too small to produce any other marked effect. When the pain is great large doses may be required, but even then the other effects they would usually produce seem frequently to be counteracted by the pain, so that they relieve it without causing drowsiness or stupor. Opium and morphine are employed in neuralgias of various kinds, such as tic, sciatica, or intercostal neuralgia, in dysmenorrhoea and in cancer. They are used to lessen both pain and inflammation in rheumatism and inflammatory conditions, such as pleurisy, pneumonia, peritonitis, cystitis. They are used to lessen pain and spasm in ordinary colic, lead colic, and in hepatic and renal colic.

Nervous System. - Opium or morphine is used to relieve sleeplessness due to almost any cause, but in cases of worry or worn-out conditions of the nervous system it is better to use bromide of potassium or chloral, as opium-taking becomes a habit. If these will not act, it may be necessary to use opium.

In fever and delirium 10 min. of tincture of opium may be given with 1/4 gr. of tartar emetic, and the effect watched.

In mania, delirium tremens, and chorea, morphine may be given subcutaneously, but bromide of potassium and chloral are often preferable.

In intense melancholia subcutaneous injection of morphine may be used, but care must be taken not to establish the opium habit. Small doses of tincture of opium (5-10 min.) by the mouth are also very useful. Care should be taken to disguise the drug so that the patient may not know what he is taking, and thus to prevent the risk of his taking opium afterwards at his own pleasure. Morphine is sometimes employed to prolong the anaesthesia of chloroform, as in excision of the upper jaw, where it is inconvenient to continue the administration of chloroform.

In malarial poisoning there appears to be a hyper-sensibility of the vaso-motor centre, so that a draught of cold air blowing on the surface, slight gastric irritation, or even slight distension of the bladder, will cause contraction of the cutaneous vessels, and shivering, in one suffering from such poisoning. Opium appears to be useful in such conditions, probably by lessening the excitability of the vaso-motor centre.

Opium-eaters are frequently found in the fen districts, and in some forms of ague in the tropics opium has been of service when quinine has failed, and the two drugs combined have been still more serviceable than either alone.

Contra-indications: (1) Childhood, till the age of 5 years. Either abstain totally, or be most cautious in the use of opium and its preparations, as small doses act with disproportionate power.

(2) Blocking of the bronchial tubes by excessive secretion.

(3) Congestion of the brain, with suffused eyes and contracted pupils.