ASTHMATIC DISEASES OF THE LUNGS. Spasmodic Asthma.
In the strict use of the word, asthma is a spasmodic disease, in which the organic muscular fibres surrounding the bronchial tubes are thrown into a state of acute spasm, so that the entrance of air into the air vesicles, in which the bronchial passages finally ter minate, is impeded. The spasmodic paroxysms are often sudden and rapid, but may be unattended by fever. The breathing dur ing the attack is very oppressed and difficult; the suffocation is severe; the body dark, often cold, and enfeebled.
Asthma may be excited in those who are subject to it by causes of irritation lying away from the lungs, and one of the most common excitants of it is irritation in the stomach or intes tines, from improper food or defective digestive power. It occurs in all periods of life, is hereditary in character, and rarely passes altogether away in those who are affected by it, although it may be much controlled by care in diet and regimen. Death is not common during the paroxysm, the relaxation incident to dying, if I may so express it, having in itself a tendency to cause relaxation of the spasmodically contracted muscular fibres. There are two varieties of asthma.
Pure spasmodic asthma. As above described.
Symptomatic asthma. In which the asthma is an attendant or indication of some other disease, such as heart disease. Thus we hear of cardiac asthma and bronchial asthma.
Ray asthma, placed by the Royal College first in the list of the local diseases of the lungs, is a spasmodic affection occurring in some persons during the bay season, when the odor of fresh hay is present in the fields. There is, commonly, a sense of catarrh or cold in this affection, with some discharge from the nose, and with paroxysms of severe spasmodic cough, brought on much after the same manner as coughing and sneezing are brought on by taking snuff. The disease is supposed to be due to the in halation of fine particles derived from the flowers of grasses, and which specially affect particular individuals. The powdered par ticles of ipecacuanha produce a similar condition in some persons. I have observed that from Russian hemp particles are given off which cause a most aggravated form of disease of a similar kind in susceptible subjects. Hay asthma continues as long as the cause remains in action, and it may be prolonged for several days, or even for some weeks, after the cause of it has ceased to exist in the air.
Under the general term asthma, by which is meant difficult breathing, not necessarily from spasm, but from disease caused by the inhalation of dusts which create destruction of function in portions of the lungs, there are included several kinds of lung disease incident to different callings. We shall see the details of these affections more fully as we proceed, in another part of this work, but the typical asthmas thus referred to may be named, so as to make our record so far complete. They are : These asthmas are all specially connected with the occupations by which they are defined.