The treatment of respiratory disorders if it is to be thoroughly rational, must be founded upon the considerations given in the four preceding sections. The student will understand that the treatment of the disease on which these disorders depend must be conducted at the same time; and that we are here concerned only with symptoms.

Dyspnoea.-The phenomena of dyspnoea strongly indicate the necessity of providing, by every possible means, for increased freedom and force of respiration-of assisting hyperpnoea by admitting as much air as possible into the chest. The air must be pure and mild, that is, abundant, fresh, warm, and moist. The muscles of respiration must be free to act upon the chest, and every available muscle of extraordinary respiration must be relieved from other employment and ready to be called into use: the shoulders must be raised, the chest freed from restraint and weight, in front, behind, and especially below (by adopting the sitting posture), and the arms must he capable of being fixed, if necessary. The circulation also must he spared by absolute rest and other measures.

Medicinal treatment must then be ordered, the first end to be secured being the rapid clearance of the respiratory passages of the products of disease. This is done by stimulating the natural provisions for relief, namely cough and expectoration, by means of expectorants. The cough must not only be induced or strengthened, but accompanied by a more profuse flow of watery mucus, so as to facilitate discharge of the sputa. Fortunately, most expectorants produce the second effect as well as the first; and we are left free to select our remedy, more from a consideration of its concomitant effect upon the circulation, i.e. according as a sedative or a stimulant effect is desired. Cardio-vascular sedatives, such as Antimony, Ipecacuanha, Iodides, and Alkalies, or a combination of these, will be preferred as expectorants in the first stage of inflammatory obstruction of the passages {acute bronchitis), salines being specially valuable as liquefying the mucus; whilst stimulants, such as Ammonia, Scilla, and the large Aromatic group, will be indicated at a later stage when the heart threatens to fail, or at any period in weak subjects. The Aromatics, such as Camphor, the Balsams of Benzoin, Tolu and Peru, Ammoniacum and Turpentine, also act as disinfectants, if the products have become purulent and tend to decompose. In every instance the value of warm liquid food must be taken advantage of.

Emetics may be employed to empty the respiratory passages when blocked by a comparatively large and solid mass, such as a croupous membrane; to empty dilated bronchial tubes when these and the lung-tissue have lost their elasticity from age and debility; and occasionally, when the necessary cough can no longer be induced on account of extreme weakness, and asphyxia is threatening. In the last-named case much danger attends such a depressing method of treatment; and in every instance comparatively mild and yet certain emetics must be selected for respiratory purposes, such as Ipecacuanha and Carbonate of Ammonia, or Sulphate of Zinc if these fail.

Posture is frequently of value in emptying the bronchi, or cavities communicating with them, of pus and other products. The body may sometimes be even inverted with success.

If asphyxia occur, artificial respiration must be carried out.

Dyspnoea may also be relieved by the abstraction of blood, or by its diversion from the thorax into the abdominal vessels, where its volume can be reduced by a free purge. This sometimes affords great relief at the commencement of acute bronchitis. Diaphoretics and diuretics are valuable under similar circumstances. But instead of reducing the volume of blood, or in addition to this means, we may prevent its accumulation in the lungs and right side of the heart by stimulant measures. Thus Carbonate of Ammonia not only irritates the nerves and glands of the bronchial mucosa, liquefies the secretion, and strengthens the respiratory centre, but is a powerful cardio-vascular stimulant, aiding the ventricular contractions, emptying the veins, and filling the arteries. Other circulatory stimulants which may not possess expectorant action are so far also indicated in respiratory distress, such as applications of mustard to the chest-wall and warm alcoholic drinks.

In dyspncea from consolidation of the lung in acute pneumonia, i.e. from diminished respiratory area, the plan of treatment must be considerably modified. Here there is neither lack of air nor lack of blood; only they cannot come into mutual contact. The respiratory rate is greatly accelerated, and the air thus constantly changed; the cardiac rhythm is also accelerated, and the blood thus constantly renewed. The therapeutist appreciates this natural provision, and directs his measures to the support of the powers thus severely taxed: to maintain the strength of the respiratory muscles, and, most anxiously of all, to sustain the heart, by failure of which death is most likely to occur. Whilst, therefore, the strength is spared in every way, food is to be freely given with Alcohol, Scilla, Ammonia, and Digitalis; the atmosphere maintained as pure and fresh as possible; and the accompanying fever, which is attended by cardiac depression, steadily combated by suitable non-depressing measures.

Dyspnoea with spasm is so far to be treated on the same principles as other forms of obstructive dyspnoea, but the spasmodic element must be separately considered. Practically, by far the most rapid and powerful antispasmodics are, as we have seen, certain expectorants, including Tobacco, Ipecacuanha, etc., which provoke greater spasm, violent cough, and profuse watery secretion, thus instantly clearing the passages and relaxing the mucous membrane. A milder and equally rational class of antispasmodics to be employed in asthma are the direct depressants of the nervo-muscular structure of the bronchi, the chief of which are Belladonna, Hyoscyamus, Stramonium and their Alkaloids, Tobacco, and Lobelia, whether in solution or in the form of smoke. Conium is much less useful. Moist warm air or steam may be of great service as the only available remedy. Opium, Chloral, Cannabis Indica, and other narcotics, will frequently relieve spasm, but such powerful respiratory depressants are highly objectionable in threatening asphyxia. Nitrite of Amyl may instantly give relief, hut the spasm may as quickly return; Nitre fumes suit some cases. Small doses of Spirit of Ether or Chloroform in solution are frequently most valuahle, because so rapidly diffusible; and a mixture of Ammonia, Carbonate of Ammonia, Spirit of Ether, and Aromatics is one of the best combinations for general use.

Cough has been already referred to as far as it is to be encouraged, for the relief of movable obstruction and dyspnoea. When it is not only ineffectual but harmful, for instance when due to swelling, morbid growths, or purely nervous causes, it demands immediate relief. It cannot, however, be too much insisted on that the tendency of young practitioners is towards an abuse of this class of remedies, by prescribing them in a routine fashion for every case of cough, irrespective of its cause. Narcotics are powerful depressants of the respiratory centre, as well as of many other organs, including the heart; and, which is of equal consequence, they interfere with the reflection which originates useful cough and increased breathing, and ultimately aggravate the condition which they temporarily relieve. It is only when the cause of cough cannot be removed, that the irritability of the nervo-muscular apparatus may be safely reduced by respiratory sedatives, such as Opium, Chloroform, Ether and Chloral, Alcohol and Conium, according to circumstances, although warm moist air, warm liquid food, poultices to the chest, and acids or demulcents for the throat will often suffice to give relief. Several of these measures may be topically employed by insufflation, inhalation, gargling, or direct application, and when given internally they are advantageously combined with expectorants, which shall remove any movable irritant from the passages. When all but powerful opiates have failed to arrest protracted fits of coughing, as in phthisis, frequent small meals of warm liquid nutritious food, night as well as day, or pure alcoholic stimulants, will often give great relief. When the sputa are excessive, anti-expectorant measures may be demanded, and will consist in a fresh bracing atmosphere, dry simple food, the avoidance of alcohol, and the exhibition of Acids, Bitters, and probably Iron internally.

Hemorrhage from the respiratory organs must be treated on general principles. Rest must be secured not only by bodily quiet, but by the reduction of the movements of the lungs to a minimum, by strapping the chest locally and recommending voluntary restraint of respiration and cough.

Pain and the other forms of distress in connection with this system are easily arrested by direct respiratory sedatives, such as Opium, but, as we have seen, not without considerable risk. The greatest discrimination must, therefore, be exercised in having recourse to these remedies, and the routine use of them is to be deprecated. Indirect measures, including the removal of the cause of distress, and external application to the chest, are alone to be employed if possible.