Part 35 (1/2)

522. _The quant.i.ty of air inhaled is modified by the capacity of the respiratory organs._ The necessity of voluminous lungs may he elucidated by the following experiment: Suppose a gill of alcohol, mixed with a gill of water, be put into a vessel having a square foot of surface, and over the vessel a membrane be tied, and that the water will evaporate in twenty-four hours. If the surface had been only six inches square, only one fourth of the water would have evaporated through the membrane in the given time. If the surface had been extended to two square feet, the water would have evaporated in twelve hours.

523. Apply this principle to the lungs: suppose there are two hundred feet of carbonic acid to be carried out of the system every twenty-four hours. This gas, in that time, will pa.s.s through a vesicular membrane of two thousand square feet. If the lungs were diminished in size, so that there would be only one thousand square feet of vesicular membrane, the amount of carbonic acid would not, and could not, be eliminated from the system. Under such circ.u.mstances, the blood would not be purified.

524. Again; suppose the two thousand square feet of membrane would transmit two hundred cubic feet of oxygen into the system every twenty-four hours. If it should be diminished one half, this amount of oxygen would not pa.s.s into the blood. From the above ill.u.s.trations we may learn the importance of well-developed chests and voluminous lungs; for, by increasing the size of the lungs, the oxygen is more abundantly supplied to the blood, and this fluid is more perfectly deprived of its carbon and hydrogen.

What does this hereditary transmission prove? 522. How is the necessity of voluminous lungs ill.u.s.trated? 525. How is this principle applied to the interchange of products in the lungs?

525. The chest is not only most expanded at its lower part, but the portion of the lungs that occupies this s.p.a.ce of the thoracic cavity contains the greater part of the air-cells; and, from the lower two thirds of the lungs the greatest amount of carbonic acid is abstracted from the blood, and the greatest amount of oxygen gas is conveyed into the circulating fluid. Hence, contracting the lower ribs is far more injurious to the health than diminis.h.i.+ng the size of the upper part of the chest.

526. The question is often asked, Can the size of the chest and the volume of the lungs be increased, when they have been injudiciously compressed, or have inherited this unnatural form? The answer is in the affirmative. The means for attaining this end are, a judicious exercise of the lungs, by walking in the open air, reading aloud, singing, sitting erect, and fully inflating the lungs at each act of inspiration. If the exercise be properly managed and persevered in, it will expand the chest, and give tone and health to the important organs contained in it. But, if the exercise be ill-timed or carried to excess, the beneficial results sought will probably not be attained.

_Observation._ Scholars, and persons who sit much of the time, should frequently, during the day, breathe full and deep, so that the smallest air-cells may be fully filled with air. While exercising the lungs, the shoulders should be thrown back and the head held erect.

527. _The movement of the ribs and diaphragm is modified by the dress._ When the lungs are properly filled with air, the chest is enlarged in every direction. If any article of apparel is worn so tight as to prevent the full expansion of the chest and abdomen, the lungs, in consequence, do not receive air sufficient to purify the blood. The effect of firm, unyielding clothing, when worn tight, in preventing a due supply of air to the lungs, may be shown by the following ill.u.s.tration.

525. Why is it more injurious to contract the lower part of the chest than the upper? 526. How can the size of the chest be increased when it is contracted? Give the observation. 527. How is the movement of the ribs and diaphragm modified?

_Ill.u.s.tration._ If the diameter of a circle is three feet, the circ.u.mference will be nine feet. If the diameter is extended to four feet, the circ.u.mference will be increased to twelve feet. Should a tight band be thrown around a circle of nine feet, its diameter cannot be increased, for the circ.u.mference cannot be enlarged.

528. Any inelastic band, drawn closely around the lower part of the chest, or the abdomen, below the ribs, operates like the band in the preceding ill.u.s.tration, in restricting the movement of the ribs. When any article of dress encircles either the chest or abdomen, so as to prevent an increase of its circ.u.mference, it has an injudicious tendency, as it prevents the introduction of air in sufficient quant.i.ties to purify the blood. The question is not, How much restriction of the respiratory movements can be endured, and life continue? but, Does any part of the apparel restrict the movements? If it does, it is a violation of the organic laws; and though Nature is profuse in her expenditures, yet sooner or later, she sums up her account.

529. In determining whether the apparel is worn too tight, inflate the lungs, and, if no pressure is felt, no injurious effects need be apprehended from this cause. In testing the tightness of the dress, some persons will contract to the utmost the abdominal muscles, and thus diminish the size of the chest, by depressing the ribs; when this is done, the individual exclaims, ”How loose my dress is!” This practice is both deceptive and ludicrous. A good test is, to put the hand on the chest below the arm; if there is no movement of the ribs during respiration, the apparel is too tight. The only reliable test, however, is a full inflation of the lungs.

How is the effect of unyielding clothing, when worn tight, ill.u.s.trated?

528. What effect has an inelastic band upon the lower part of the chest? What question is asked? 529. How can we determine whether the apparel is worn too tight?

_Observation._ Many individuals do not realize the small amount of force that will prevent the enlargement of the chest. This can be demonstrated by drawing a piece of tape tightly around the lower part of the chest of a vigorous adult, and confining it with the thumb and finger. Then endeavor fully to inflate the lungs, and the movement of the ribs will be much restricted.

530. _The position in standing and sitting influences the movement of the ribs and diaphragm._ When the shoulders are thrown back, and when a person stands or sits erect, the diaphragm and ribs have more freedom of motion, and the abdominal muscles act more efficiently; thus the lungs have broader range of movement than when the shoulders incline forward, and the body is stooping.

531. _Habit exercises an influence upon the range of the respiratory movements._ A person who has been habituated to dress loosely, and whose inspirations are full and free, suffers more from the tightness of a vest or waistband, than one, the range of movements of whose chest has long been subjected to tight lacing.

532. _The condition of the brain exercises a great influence upon respiration._ If the brain is diseased, or the mind depressed by grief, tormented by anxiety, or absorbed by abstract thought, the contractile energy of the diaphragm and muscles that elevate the ribs, is much diminished, and the lungs are not so fully inflated, as when the mind is influenced by joy or other exhilarating emotions. The depressing pa.s.sions likewise lessen the frequency of respiration. By the influence of these causes, the blood is but partially purified, and the whole system becomes enfeebled. Here we may see the admirable harmony between the different parts of the body, and the adaptation of all the functions to each other.

Give another test. How can the amount of pressure necessary to prevent the enlargement of the chest be demonstrated? 530. Show the effect of position on the movements of the ribs and diaphragm. 531. Show the effect of habit on the respiratory movements. 532. State the influence of the mind upon respiration.

533. As the quant.i.ty of air inhaled at each unimpeded inspiration in lungs of ample size, is about forty cubic inches, it follows, if the movement of the ribs and diaphragm is restricted by an enfeebled action of the respiratory muscles, or by any other means, the blood will not be perfectly purified. In the experiment, ( 522, 523,) suppose forty cubic inches of air must pa.s.s over the membrane twenty times every minute, and that this is the amount required to remove the vapor which arises from the membrane; if only half of this amount of air be supplied each minute, only one half as much water will be removed from the alcohol through the membrane in twenty-four hours; consequently, the alcohol would be impure from the water not being entirely removed.