When managed with due regard to the natural powers of the individual, and so as to avoid effort and fatigue, reading aloud becomes a very useful and invigorating exercise. In forming and undulating the voice, not only the chest, but also the diaphragm and abdominal muscles are in constant action, and communicate to the stomach and bowels a healthy and agreeable stimulus. Where the voice is raised and the elocution is rapid, the muscular effort becomes fatiguing; but when care is taken not to carry reading aloud so far at one time as to excite a sensation of soreness or fatigue in the chest, and the exercise is duly repeated, it is extremely useful in developing and giving tone to the organs of respiration and to the general system.
"Vocal music is also very useful, by its direct effect on the constitution. It was the opinion of Dr. Rush, that young ladies especially, who, by the custom of society, are debarred from many kinds of salubrious exercise, should cultivate singing, not only as an accomplishment, but as a means of preserving health. He particularly insists that it should never be neglected in the education of females; and states that, besides its salutary operation in enabling them to soothe the cares of domestic life, and quiet sorrow by the united assistance of the sound and sentiment of a properly chosen song, it has a still more direct and important effect. 'I here introduce a fact,' he remarks, 'which has been suggested to me by my profession, and that is, that the exercise of the organs of the breast by singing contributes very much to defend them from those diseases to which the climate and other causes expose them. The Germans are seldom afflicted with consumption, nor have I ever known but one instance of spitting blood among them. This, I believe, is in part occasioned by the strength which their lungs acquire by exercising them frequently in vocal music, for this constitutes an essential branch of their education. The music-master of our academy has furnished me with an observation still more in favor of this opinion. He informed me that he had known several instances of persons who were strongly disposed to consumption, who were restored to health by the exercise of their lungs in singing.'"[10]
Bathing or ablution, when conducted as recommended on pages 60 and 61, is not only a means of cleanliness and of exciting a healthy action in the skin, but it constitutes, at the same time, a most admirable exercise. If a lodging-room has been properly ventilated by leaving open windows, or otherwise, so that the air is pure and healthful in the morning, ten or fifteen minutes spent in bathing and friction, with a proper exercise of the muscles of the back and abdomen, will contribute more to invigorate the system and promote the general health than twice the amount of exercise taken at any other time or in any other way.
From the foregoing remarks, it appears that the most perfect of all exercises are those which combine the free play of all the muscles of the body, mental interest and excitement, and the unrestrained use of the voice.
CHAPTER IV.
THE LAWS OF HEALTH. PHILOSOPHY OF RESPIRATION.
We instinctively shun approach to the dirty, the squalid, and the diseased, and use no garment that may have been worn by another. We open sewers for matters that offend the sight or the smell, and contaminate the air. We carefully remove impurities from what we eat and drink, filter turbid water, and fastidiously avoid drinking from a cup that may have been pressed to the lips of a friend. On the other hand, we resort to places of assembly, and draw into our mouths air loaded with effluvia from the lungs, skin, and clothing of every individual in the promiscuous crowd—exhalations offensive, to a certain extent, from the most healthy individuals; but when arising from a living mass of skin and lungs in all stages of evaporation, disease, and putridity, they are in the highest degree deleterious and loathsome.—Birnan.
Respiration is usually defined as the process by which air is taken into the lungs and expelled from them. It explains the changes that take place in these organs, in the conversion of chyle and venous, or worn-out blood, into arterial or nutrient blood. In order to be clearly understood, I must premise a few observations on the circulation of the blood.[11] The blood circulating through the body is of two different kinds; the one red or arterial, and the other dark or venous blood. The former alone is capable of affording nourishment and supporting life. It is distributed from the left side of the heart all over the body by means of a great artery, which subdivides in its course, and ultimately terminates in myriads of very minute ramifications closely interwoven with, and in reality constituting a part of, the texture of every living part. On reaching this extreme point of its course, the blood passes into equally minute ramifications of the veins, which in their turn gradually coalesce, and form larger and larger trunks, till they at last terminate in two large veins, by which the whole current of the venous blood is brought back in a direction contrary to that of the blood in the arteries, and poured into the right side of the heart. On examining the quality of the blood in the arteries and veins, it is found to have undergone a great change in its passage from the one to the other. The florid hue which distinguished it in the arteries has disappeared, and given place to the dark color characteristic of venous blood. Its properties, too, have changed, and it is now no longer capable of sustaining life.
Two conditions are essential to the reconversion of venous into arterial blood, and to the restoration of its vital properties. The first is an adequate provision of new materials from the food to supply the place of those which have been expended in nutrition, and the second is the free exposure of the venous blood to the atmospheric air. The first condition is fulfilled by the chyle, or nutrient portion of the food, being regularly poured into the venous blood just before it reaches the right side of the heart, and the second by the important process of respiration, which takes place in the air-cells of the lungs. The venous blood, having arrived at the right side of the heart, is propelled by the contraction of that organ into a large artery, leading directly, by separate branches, to the two lungs, and hence called the pulmonary artery. In the innumerable branches of this artery expanding themselves throughout the substance of the lungs, the dark blood is subjected to the contact of the air inhaled in breathing, and a change in the composition both of the blood and of the inhaled air takes place, in consequence of which the former is found to have reassumed its florid or arterial hue, and to have regained its power of supporting life. The blood then enters minute venous ramifications, which gradually coalesce into larger branches, and at last terminate in four large trunks in the left side of the heart, whence the blood, in its arterial form, is again distributed over the body, to pursue the same course and undergo the same change as before.