We must here notice:

1. The products of various morbid processes on the mucous membrane of any portion of the air-passages, such as blood, or as mucus (which may collect in large quantity, and may present many peculiarities of character, being gray or pearl-colored, colorless, transparent, aqueous, viscid, glassy, of a creamy, whitish-yellow color, or puriform), or as true pus, or membranous exudations (croup-membranes), or as ichorous fluid, tubercle and tuberculous pus, fragments of necrosed cartilage, ossified bronchial cartilage, etc.

2. Products of morbid processes, occurring external to the air-passages, and finding their way into them, either by the natural passages, or by a destruction of tissue, - as for instance blood (usually in considerable quantity), in a coagulated or fluid state from the lungs or from aneurisms which have opened into the air-passages; serous frothy fluid (bronchial froth) from the parenchyma of the lungs; pus and ichor arising most frequently from abscesses in the lungs and bronchial glands or in the vertebrae; the corrosion of a bronchial trunk may allow the fluid of empyema to be discharged into the air-passages, and by another process the contents of an hepatic abscess may make their way into the bronchial tubes: the ichor of cancer, principally arising from cancerous destruction of the oesophagus; masses of tubercle; calcareous and stony concretions, with which, as produced in the air-passages, we must place cretified blennorrhoeal mucus and tubercle; and, finally, acephalocysts from the lungs, liver, and thyroid gland (Portal).

3. Foreign Bodies

Foreign bodies which:

(a.) Find their way from the pharynx and oesophagus, or even from the stomach and intestinal canal, by means of abnormal modes of communication, or by the natural passages, into the air-tubes. The most common are fluids that have been imbibed, and having made their way through ulcerous or cicatrized strictures, penetrate into the trachea or bronchi. Amongst the foreign bodies proceeding from the stomach and intestinal canal, we must especially notice the round worm, which has been seen both by ancient and modern observers in the pharynx in children, and, crawling into the glottis, has produced death by suffocation.

(b.) Articles of food may become impacted in the glottis, in cases in which the act of deglutition is impeded by inflammation, and degeneration of the muscular walls of the pharynx, or by enlarged tonsils, or is inattentively performed from haste and carelessness as in imbeciles, or is interrupted by coughing, sneezing, or laughing. These accidents are most liable to occur when, from atrophy, rigidity, or malformation, the epiglottis is no longer able sufficiently to protect the glottis; and the substances most commonly causing them are large pieces of tough meat, skin, and gristle.

(c.) Foreign bodies which accidentally enter the glottis independently of any intentional act of swelling, and either fall into the trachea and bronchi, or are forced into them by an automatic movement of deglutition. Cases are recorded in which the following bodies have got in the air-passages: - small arrows, plum and cherry stones, small coins, natural and artificial teeth, grains of corn, nails, pebbles, and fragments of glass. In favorable cases they are soon removed by coughing; but otherwise they remain for a long time in the air-passages, inducing not only inflammation of the mucous membrane, pneumonia, and ultimately suppuration, but even destruction of the walls of the bronchial tubes. This they may effect in various ways, and they may even penetrate into the adjacent bloodvessels. I may here mention the following singular case: A little boy sucked a dart from a blowing-tube. Its feathered portion was downwards as it descended the trachea, and from thence it went into the left bronchus. On the twelfth day he died from hemorrhage of the air-passages, having at the same time symptoms of pneumonia. Dissection revealed bronchitis, especially on the left side, and hepatization of the left lower lobe. The dart was lying loose in the left bronchus, with its feathered part downwards. Opposite to the opening of this bronchus into the trachea, in the cartilaginous wall of its right side, there was an injured spot of about the size of a hemp-seed, and through this there was a perforation into the adjacent arteria innominata. In the paroxysms of coughing, the point of the dart was being constantly forced against this spot in the right tracheal wall, which lay opposite to the axis of the left bronchus; and in this way the fatal lesion was ultimately produced.

It is neither unimportant nor uninteresting to remark that in the majority of cases, these foreign bodies fall into the right bronchus (Key). This is undoubtedly dependent on its larger size, on the greater obtuse-ness of the angle that it makes with the trachea, and on the greater energy of the current of air rushing through it. Moreover this is in accordance with the well-known fact that in new-born children respiration is effected sooner and more perfectly by the right bronchus and lung than by the left.