Zoonomia; Or, the Laws of Organic Life, Vol. II

by Erasmus Darwin

It may likewise sometimes happen, that the disagreeable sensation, occasioned by the congestion of lymph in the air-cells in the humoral or hydropic asthma, may induce voluntary convulsions of the respiratory organs only to relieve the pain, without any sensitive actions of the pulmonary absorbents to absorb and eliminate the congestion of serous fluid; and thus the same cause may occasionally induce either the humoral or convulsive asthma.

The humoral asthma has but one remote cause, which is the torpor of the pulmonary vessels, like that which occurs on going into the cold bath; or the want of absorption of the pulmonary lymphatics to take up the lymph effused into the air-cell. Whereas the convulsive asthma, like other convulsions, or epilepsies, may be occasioned by pain in almost any remote part of the system. But in some of the adult patients in this disease, as in many epilepsies, I have suspected the remote cause to be a pain of the liver, or of the biliary ducts.

The asthmas, which have been induced in consequence of the recess of eruptions, especially of the leprous kind, countenance this opinion. One lady I knew, who for many years laboured under an asthma, which ceased on her being afflicted with pain, swelling, and distortion of some of her large joints, which were esteemed gouty, but perhaps erroneously. And a young man, whom I saw yesterday, was seized with asthma on the retrocession, or ceasing of eruptions on his face.

The convulsive asthma, as well as the hydropic, are more liable to return in hot weather; which may be occasioned by the less quantity of oxygen existing in a given quantity of warm air, than of cold, which can be taken into the lungs at one inspiration. They are both most liable to occur after the first sleep, which is therefore a general criterion of asthma. The cause of this is explained in Sect. XVIII. 15. and applies to both of them, as our sensibility to internal uneasy sensation increases during sleep.

When children are gaining teeth, long before they appear, the pain of the gums often induces convulsions. This pain is relieved in some by sobbing and screaming; but in others a laborious respiration is exerted to relieve the pain; and this constitutes the true asthma convulsivum. In other children again general convulsions, or epileptic paroxysms, are induced for this purpose; which, like other epilepsies, become established by habit, and recur before the irritation has time to produce the painful sensation, which originally caused them.

The asthma convulsivum is also sometimes induced by worms, or by acidity in the stomachs of children, and by other painful sensations in adults; in whom it is generally called nervous asthma, and is often joined with other epileptic symptoms.

This asthma is distinguished from the peripneumony, and from the croup, by the presence of fever in the two latter. It is distinguished from the humoral asthma, as in that the patients are more liable to run to the cold air for relief, are more subject to cold extremities, and experience the returns of it more frequently after their first sleep. It is distinguished from the hydrops thoracis, as that has no intervals, and the patient sits constantly upright, and the breath is colder; and, where the pericardium is affected, the pulse is quick and unequal. See Hydrops Thoracis, [I. 2. 3. 14].

M. M. Venesection once. A cathartic with calomel once. Opium. Assafœtida. Warm bath. If the cause can be detected, as in toothing or worms, it should be removed. As this species of asthma is so liable to recur during sleep, like epileptic fits, as mentioned in Section XVIII. 15. there was reason to believe, that the respiration of an atmosphere mixed with hydrogen, or any other innocuous air, which might dilute the oxygen, would be useful in preventing the paroxysms by decreasing the sensibility of the system. This, I am informed by Dr. Beddoes, has been used with decided success by Dr. Ferriar. See Class [II. 1. 1. 7].

[11]. Asthma dolorificum. Angina pectoris. The painful asthma was first described by Dr. Heberden in the Transactions of the College; its principal symptoms consist in a pain about the middle of the sternum, or rather lower, on every increase of pulmonary or muscular exertion, as in walking faster than usual, or going quick up a hill, or even up stairs; with great difficulty of breathing, so as to occasion the patient instantly to stop. A pain in the arms about the insertion of the tendon of the pectoral muscle generally attends, and a desire of resting by hanging on a door or branch of a tree by the arms is sometimes observed. Which is explained in Class [I. 2. 3. 14]. and in Sect. XXIX. 5. 2.

These patients generally die suddenly; and on examining the thorax no certain cause, or seat, of the disease has been detected; some have supposed the valves of the arteries, or of the heart, were imperfect; and others that the accumulation of fat about this viscus or the lungs obstructed their due action; but other observations do not accord with these suppositions.