534. Restrain the elevation of the ribs and depression of the diaphragm, so that the quantity of air conveyed into the lungs will be reduced to twenty cubic inches, when forty are needed, and the results will be as follows: Only one half of the carbonic acid will be eliminated from the system, and the blood will receive but one half as much oxygen as it requires. This fluid will then be imperfectly oxydated, and partially freed of its impurities. The impure blood will be returned to the left side of the heart, and the whole system will suffer from an infringement of organic laws.
533. Illustrate the effect upon the blood when the respiratory muscles are enfeebled in their action. 534. Show how the blood is imperfectly purified by restricting the movements of the ribs and diaphragm.
535. Scrofula, or consumption, frequently succeeds a depressed state of the nervous system. These diseases arise from the deposition of tuberculous matter in different parts of the body. Those individuals who have met with reverses of fortune, in which character and property were lost, afford painful examples. Hundreds yearly die from the effect of depressed spirits, caused by disappointed hopes, or disappointed ambition.
Illustration. A striking instance of the effects of mental depression is related by Lænnec. In a female religious establishment in France, great austerities were practised; the mind was absorbed in contemplating the terrible truths of religion, and in mortifying the flesh. The whole establishment, in the space of ten years, was several times depopulated—with the exception of the persons employed at the gate, in the kitchen, and garden—with that fatal disease, consumption. This institution did not long continue, but was suppressed by order of the French government.
536. The purity of the blood is influenced by the condition of the lungs. When the bronchial tubes and air-cells have become partially impervious to air, from pressure upon the lungs, from fluids in the chest, from tumors, or from the consolidation of the cells and tubes from disease,—as inflammation, or the deposition of yellow, cheesy matter, called tubercles,—the blood will not be purified, even if the air is pure, the lungs voluminous, and the respiratory movements unrestricted, as the air cannot permeate the air-cells.
Observations. 1st. The twenty-three who escaped immediate death in the Black Hole of Calcutta were soon attacked with inflammation of the lungs, by which these organs were 248 consolidated, and thus prevented the permeation of air into their cells. This disease of the lungs was caused by breathing vitiated air.
535. Mention some of the effects of mental depression upon the body. What is related by Lænnec? 536. Does the condition of the lungs influence the purity of the blood? Mention some of the conditions that will impede the oxydation of blood in the lungs. What occurred to those persons who escaped death in the Black Hole of Calcutta?
2d. One of the precursory symptoms of consumption is the feeble murmur of respiration in the upper part of the lungs. This condition of these organs is produced by, or frequently follows, mental depression, the breathing of impure air, the stooping position in standing or sitting, and the restriction of the movements of the ribs and diaphragm.
3d. Persons asphyxiated by carbonic acid, water, strangling, or any noxious air, after resuscitation, are usually affected with coughs and other diseases of the lungs.