2. The second office of the lungs is a depurating or cleansing office. The blood, to the extent of three gallons or more, in the adult, is sent by the heart to all parts of the body with great rapidity, to nourish it. In the performance of this duty, its vitality, heat, and nutritious powers are gradually exhausted, and it becomes loaded with carbon and other impurities.

The blood, with its impurities, comes back from all parts of the system through the veins to the right side of the heart, whence it is immediately sent, commingled with the chyle, of which I have before spoken, — through what are called pulmonary arteries, into the lungs. By means of the very minute division and subdivision of these arteries in the lungs, it is, lastly, spread over the coats of the innumerable air cells which are found there. Here, from the thinness of these cells, it is supposed that the blood parts with its carbon, and becomes what the chemists call oxidated or oxygenated. I shall not in a brief lecture undertake to say how this oxidation takes place. It is sufficient for every practical purpose to know that the blood is depurated or cleansed by it.

3. Another office of the lungs is to serve as the great fireplace of the system; for though heat is probably generated more or less by all the more active and vital parts of the body, yet it is admitted, on all hands, that the work of calorification is especially performed in the lungs. Our power to resist cold or heat in excess depends more on the strength of our lungs than on every thing else.

One more pulmonary office remains to be mentioned. The lungs have power to transmit or transude much water in the state of vapor, which in warm air is invisible, but in cold or damp weather is discernible, as if it were a dense steam issuing from the body. Whether the lungs really absorb, -I mean in a natural and healthy state, as it is known the skin

-

does, is not so well established. In extreme cases, however, it is highly probable that, instead of transudation, their office is inverted, and they imbibe water, at least to some small extent. I have several times wholly abstained from drink from six to nine or ten months in succession. True, my food embraced fruits and many succulent vegetables; yet the fluid excretions of the body during these experiments appeared to exceed the amount of liquid existing in my food. Whence could this excess have been obtained except through the lungs?

III. LAWS OF THE LUNGS.

LAW 1. The Lungs should be made as capacious as possible.

By this is not only meant that they should be made by education as large as possible, but that they should be expanded or distended as much as possible at every inspiration.

The importance of capacious lungs is every day seen. Men with large chests are not only stronger and less liable than others to diseases of these organs, but more tenacious of life generally. I have known instances where, for several days, life seemed almost extinct except in the lungs; and yet these, as a well-fortified citadel, still held out. They are also better able, as we have seen, to resist the extremes of heat and cold.

But their importance is revealed most clearly by science. If their great offices are to form and purify the blood, and if this purification depends chiefly on having an abundant supply of good air at all times within the vital domain, then does it not follow that, other things being equal, the larger the lungs are the better? And can we attach too much importance, in this point of view, to mere capacity?

Laborers, soldiers, sailors, housekeepers, and such mechanics as have widely-varied exercises and an abundance of free air, have larger lungs than those who are sedentary in their habits and are compelled to breathe bad air. Every one knows that, as a general rule, if temperate, they are the most healthy. Their inheritance is better. Injurious customs have not so much affected them as others. Their position of body is more favorable; they sit less, and when they do sit, they do not bend forward as much as others. Few things do more mischief to the lungs than standing or sitting day after day with the head and shoulders pitched forward, as in the case of tailors, shoemakers, stonecutters, engravers, and the like.

All the airy exercises and employments I have mentioned - and many others which might be named-tend to keep the cells of the lungs fully inflated, and by degrees to enlarge the whole cavity of the chest. I have sometimes thought, moreover, that those who are employed in the open air sing and converse more than others; and the Germans say that singing is so remedial as to cure even consumption.

LAW 2. The Lungs must have free Motion.

This rule or law is intended to apply to both kinds of motion that of the diaphragm and that of the chest itself. Both are most sadly neglected, and the consequences are becoming fearful in the extreme.

The free motion of the diaphragm is overlooked from life's very threshold. The manner of holding infants in, the arms is often very objectionable. I have seen the sternum, or breast bone, so distorted in this way as to leave quite a ridge at its junction with the ribs, something in shape like the keel of a boat. Children who are suffered to lie on their backs on

the bed or floor, and scramble about in their own way, a good deal, seldom have this strange appearance.

It may be said by some that these deformities only take place in the case of children who are rickety or otherwise enfeebled, since many strong children are maltreated in this way, and yet escape deformity. This is no doubt true; but it only serves to enhance the importance of our rule.

As soon as children begin to utter their little monosyllables, they are not only permitted to utter them in a listless manner, but practically taught to do so. We use them ourselves in talking with them. No wonder their lungs remain feeble, and that the diaphragm hardly seems to move while they are speaking. No wonder the chest is narrow and contracted.

Let me be fully understood. I have no objection to monosyllables. Let children be children, and let their words be as small as they please. Let them be encouraged, however, both by example and precept, to speak with energy. I would have no unnecessarily bad articulation. Every thing should be well done that is done at all.

The parent need not, and should not, indulge in mere baby talk. What he says to the child, whether monosyllables or otherwise, should be spoken plainly and fully. He should speak with all his might, and encourage the child to do the same. He should speak not only with his throat, but with his lungs; his diaphragm should move, and so should his very abdominal muscles.

Few parents are aware of the great good they might accomplish in this way, if they were but half as anxious to make men and women of their children as to transform them into monkeys and parrots, or at best into mere playthings. One third might be added to the capacity and power of the lungs by proper early cultivation.

Not only may the lungs be invigorated by proper attention to conversation, but also by early singing. It was a blessed day that first saw the Pestalozzian notions about singing fairly on our shores; and were it for no other reason than that he was instrumental in this great work, the name of Woodbridge, the geographer, should be immortalized. He not only brought us the Pestalozzian system, but roused public attention to it.

When a child sings, as well as when he speaks, he should sing with all his might. I do not mean in either case that he should holla. There is a wide difference between speaking with a full voice and bawling. The lungs should be fully inflated with air in the beginning, and kept so.

I have watched many of our distinguished singers while they were performing, and have always found that they sung with their lungs full of air; that they never suffered their stock of air to be exhausted; and that they never sung with the top of their throat merely. The lungs are a kind of bellows. Good singers work the whole bellows, and not only the bellows, but the bellows handles the abdominal muscles. which, however, should

When a child is taught to read,

be at a much later period,― he should pay the same attention to the right use of his lungs that is necessary in speaking and singing. Our reading aloud, both in family and in school, is almost any thing but what it should be. I am accustomed to attach almost as much importance to reading and speaking, as a means of strengthening the lungs, as the Germans are to singing.

Were these three things-speaking, singing, and reading properly conducted, in family and school, I have not a doubt that the capacity and vigor of the lungs might be increased by it, in the progress of a century or two, some twenty or twenty-five per cent.