The following, from the pen of an American author[18] who has written much and well on physical education, is pertinent to the subject under consideration: "We breathe bad air princ.i.p.ally as the production of our own bodies. Here is the source of a large share of human wo; and to this point must his attention be particularly directed who would save himself from disease, and promote, in the highest possible degree, his health and longevity. We must avoid breathing over the carbonic acid gas contained in the tight or unventilated rooms in which we labor or remain for a long time, whether parlors, school-rooms, counting-rooms, bed-rooms, shops, or factories. The individual who lives most according to nature--who observes with most care the laws of life and health--must necessarily throw off much carbonic acid from his lungs, if not from his skin. It does not follow, however, that because this gas is formed we are obliged to inhale it. We may change our position, change our clothing, ventilate our rooms of all sorts, shake up our bed-clothing often and air our bed, and use clean, loose, and porous clothing by night and by day. We may thus very effectually guard against injuries from a very injurious agent.

[18] From Dr. William A. Alcott's Tract on Breathing Bad Air.

"One thing should be remembered in connection with this subject which is truly encouraging. The more we accustom ourselves to pure air, the more easily will our lungs and nasal organs detect its presence. He who has redeemed his senses and restored his lungs to integrity, like him who has redeemed a conscience once deadened, is so alive to every bad impression made upon any of these, that he can often detect impurity around or within him, and thus learn to avoid it. It will scarcely be possible for such a person long to breathe bad air, or nauseous or unwholesome effluvia, without knowing it, and learning to avoid the causes which produce it. Such a person will not neglect long to remove the impurities which acc.u.mulate so readily on the surface of his body, or suffer himself to use food or drink which induces flatulence, and thus exposes either his intestines or his lungs, or the lungs of others, to that most extremely poisonous agent, sulphureted hydrogen gas. Nor will he be likely to permit the acc.u.mulation of filth, liquid or solid, around or in his dwelling. There are those whose senses will detect a very small quant.i.ty of stagnant water, or vinegar, or other liquids, or fruit, or changed food in the house, or even the presence of those semi-putrid substances, wine and cider. But some will indeed say that such integrity of the senses would be an annoyance rather than a blessing. On the same principle, however, would a high degree of conscientiousness in regard to right and wrong in moral conduct be a curse to us. If it be desirable to have our physical sense of right and wrong benumbed, it is so to have our moral sense benumbed also. Yet what person of sense ever complained of too tender a conscience, or too perfect a sense of right and wrong in morals?"

EXERCISE OF THE LUNGS.--Judicious exercise of the lungs, in the opinion of that eminent physiologist, Dr. Andrew Combe, is one of the most efficacious means which can be employed for promoting their development and warding off their diseases. In this respect the organs of respiration closely resemble the muscles and all other organized parts.

They are made to be used, and if they are left in habitual inactivity, their strength and health are unavoidably impaired; while, if their exercise be ill-timed or excessive, disease will as certainly follow.

The lungs may be exercised _directly_ by the use of the voice in speaking, reading aloud, or singing, and _indirectly_ by such kinds of bodily or muscular exertion as require quicker and deeper breathing. In general, both ought to be conjoined. But where the chief object is to improve the lungs, those kinds which have a tendency to expand the chest and call the organs of respiration into play ought to be especially preferred. Rowing a boat, fencing, quoits, shuttlec.o.c.k, the proper use of skipping the rope, dumb-bells, and gymnastics are of this description, and have been recommended for this purpose. All of them employ actively the muscles of the chest and trunk, and excite the lungs themselves to freer and fuller expansion. Climbing up a hill is, for the same reason, an exercise of high utility in giving tone and freedom to the pulmonary functions. Where, either from hereditary predisposition or accidental causes, the chest is unusually weak, every effort should be made, from infancy upward, to favor the growth and strength of the lungs, by the habitual use of such of these exercises as can most easily be practiced. The earlier they are resorted to, and the more steadily they are pursued, the more certainly will their beneficial results be experienced.

If the _direct_ exercise of the lungs in practicing deep inspiration, speaking, reading aloud, and singing, is properly managed and persevered in, particularly before the frame has become consolidated, it will exert a very beneficial influence in expanding the chest, and giving tone and imparting health to the important organs contained in it. As a preventive measure, Dr. Clark, in his treatise on Consumption and Scrofula, recommends the full expansion of the chest in the following manner: "We desire the young person, while standing, to throw his arms and shoulders back, and, while in this position, to inhale slowly as much air as he can, and repeat this exercise at short intervals several times in succession. When this can be done in the open air it is most desirable, a double advantage being thus obtained from the practice.

Some exercise of this kind should be adopted daily by all young persons, more especially by those whose chests are narrow or deformed, and should be slowly and gradually increased."

In this preventive measure recommended by Dr. Clark, some of our most eminent physiologists heartily concur. They also express the opinion that, for the same reason, even the crying and sobbing of children, when not caused by disease, contribute to their future health. Dr. Combe says, "The loud laugh and noisy exclamations attending the sports of the young have an evident relation to the same beneficial end, and ought, therefore, to be encouraged." But beneficial as the direct exercise of the lungs is thus shown to be, in expanding and strengthening the chest, its influence extends still further, and, as we have already seen, contributes greatly to promote the important process of digestion. If, therefore, the lungs be rarely called into active exercise, not only do _they_ suffer, but an important aid to digestion being withdrawn, the _stomach_ and _bowels_ also become weakened, and indigestion and costiveness ensue.

The exercise of what has not unaptly been called Vocal Gymnastics, and the loud and distinct speaking enforced in many of our schools, not only fortify the vocal organs against the attacks of disease, but tend greatly to promote the general health. For this purpose, also, as well as for its social and moral influences, vocal music should be introduced into all our schools. That by these and like exercises deep inspirations and full expirations are encouraged, any one may become convinced who will attend to what pa.s.ses in his own body while reading aloud a single paragraph.

There is danger of exercising the lungs too much when disease exists in the chest. At such times, not only speaking, reading aloud, and singing, but ordinary muscular exertion, ought to be refrained from, or be regulated by professional advice. When a joint is sore or inflamed, we know that motion impedes its recovery. When the eye is affected, we, for a similar reason, shut out the light. So, when the stomach is disordered, we respect its condition, and are more careful about diet.

The lungs demand a treatment founded on the same general principle. When inflamed, they should be exercised as little as possible. All violent exercise ought, therefore, to be refrained from during at least the active stages of a cold; but colds may often be entirely prevented at the time of exposure by a proper exercise of the lungs.

In conversing with an eminent physician recently on this subject, he expressed the conviction that one of the most effectual methods of warding off a cold, when exposed by wet feet or otherwise, is to take frequent deep inhalations of air. By this means the carbonic acid, which the returning circulation deposits in the lungs, is not only more effectually disengaged, but, at the same time, the greater amount of oxygen that enters the lungs and combines with the blood quickens the circulation, and thus, imparting increased vitality to the system, enables it more effectually to resist any attack that may be induced by unusual exposure.

A late medical writer, who has become quite celebrated in this country for the successful treatment of pulmonary consumption,[19] expresses the opinion that, to the consumptive, air is a most excellent medicine, and "far more valuable than all other remedies." He thinks it "the grand agent in expanding the chest." In urging the importance of habitually maintaining an erect position, he expresses the conviction that "practice will soon make sitting or standing perfectly erect vastly more agreeable and less fatiguing than a stooping posture." To persons predisposed to consumption, these hints, he thinks, are of the greatest importance. While walking, he says, "the chest should be carried proudly erect and straight, the top of it pointing rather backward than forward." To ill.u.s.trate the advantages of habitually maintaining this position, he refers to the North American Indians, who never had consumption, and who are remarkable for their perfectly erect posture while walking. "Next to this," he adds, "it is of vast importance to the consumptive to breathe well. He should make a practice of taking long breaths, sucking in all the air he can, and holding it in the chest as long as possible." He recommends the repet.i.tion of this a hundred times a day, and especially with those who have a slight cold or symptoms of weak lungs. When practiced in pure cold air, its advantages are most apparent. To increase the benefits resulting from this practice, he recommends the use of the "inhaling tube." He thinks that inhaling tubes made of silver or gold are much better than those made of wood or India-rubber. In this opinion I fully concur, for I think with him that gold and silver tubes will not so readily "contract any impure or poisonous matter." But there is another and a stronger reason why I prefer _silver_, and especially GOLD inhaling tubes, to those made of wood or India-rubber. _They would be more highly prized_ and MORE FREQUENTLY USED.

[19] S. S. Fitch, M.D., author of "Consumption Cured."

The same writer entertains the belief that about one third of all the consumptions originate from weakness of the abdominal belts. He hence, in such cases, recommends the use of the "abdominal supporter." In order to favor an erect posture and an open chest, he also recommends the use of "shoulder-braces." He says the proper use of these, with other remedies, will "entirely prevent the possibility of consumption, from whatever cause." The inhaling-tube, together with the shoulder-braces and supporter when needed, he says are perfect preventives, and should not be neglected; for if the shoulders are kept off the chest, and the abdomen is well supported, and then an inhaling tube is faithfully used, "the lungs can never become diseased. Any person in this way, who chooses to take the trouble, can have a large chest and healthy lungs."

When persons have contracted disease they may require these _artificial helps_; but it should be borne in mind that an all-wise and beneficent Creator has kindly given to each of his creatures _two inhaling tubes_, admirably adapted to their wants. He has also furnished them with a set of _abdominal muscles_ which, when properly used, have generally been found to supersede the necessity of artificial "supporters." He has, moreover, in the plenitude of his goodness, furnished each member of the human family with a good pair of _shoulder-braces_. It should also be borne in mind that Nature's shoulder-braces _improve by use_, while the artificial ones not only soon fail, but their very use generally impairs the healthy action of the natural ones; for these, like all other muscles, improve by use and become enfeebled by disuse. Parents and teachers, then, and all who have the care of the young, should encourage the correct use of Nature's inhaling tubes, shoulder-braces, and abdominal supporters; for in this way they have it in their power not only to supersede the necessity of resorting to artificial ones later in life, but of preventing much of human misery, and contributing to the permanent elevation of the race.

CHAPTER V.

THE NATURE OF INTELLECTUAL AND MORAL EDUCATION.

In the cultivation and expansion of the faculties of the mind, we act altogether upon _organized matter_--and this, too, of the most delicate kind--which, while it serves as the mediator between _body_ and _spirit_, partakes so largely of the nature, character, and essential attributes of the _former_, that, without its proper physical growth and development, all the manifestations of the _latter_ sink into comparative insignificance; so that, without a perfect organization of the _brain_, the mental powers must be proportionally paralyzed; without _its_ maintaining a healthy condition, _they_ must be rendered proportionally weak and inactive.[20]--DR. J. L. PEIRCE.

It has already been stated that there exists such an intimate connection between physical, intellectual, and moral education, that, in order duly to appreciate the importance of either, we must not view it separate and alone merely, but in connection with both of the others. However much value, then, we may attach to physical education on its own account, considering man as a corporeal being, we shall have occasion greatly to magnify its importance as we direct our attention to the cultivation and development of his mental faculties. We have no means of becoming acquainted with the laws which govern independent mind; but that mind separate from body is, from its very nature, all-knowing and intelligent, is an opinion that has obtained to a considerable extent.

Be this as it may, it does not immediately concern us in the present state. This much we know, that embodied mind acquires knowledge slowly, and with a degree of perfection depending upon the condition of the brain and the bodily organs of sense, through the medium of which mind communicates with the external world. We do not even know whether education modifies the mind itself; and, if at all, how it affects it in its disembodied state. Neither is it important that we should possess this knowledge. There is, however, much reason for believing that the mind of man in the future state will be permanently affected by, and enjoy the full benefit of, the preparatory training it has received in this life; that then, as now, it will be progressive in its attainments; and that the rapidity with which it will then acquire knowledge, and the nature of its pursuits, will depend upon the degree of cultivation, and the habits and character formed in this life.

[20] From an Essay upon the Physical and Intellectual Education of Children, written by request of the Managers of the Pennsylvania Lyceum.

From what we know of the beneficent and all-wise Creator, as manifested in his word and works, we have abundant reason for believing that our highest and enduring good will be best promoted by becoming acquainted with, and yielding a cheerful obedience to, the laws of organic mind.

Whatever the effect of education upon independent mind may be, we may rest well a.s.sured that man's everlasting well-being in the future state will be most directly and certainly reached by a strict conformity to those laws which regulate mind in its present mode of being. It should be borne in mind, also, that just in proportion as man remains ignorant of those laws, or, knowing them, disregards them, will he fail to secure his best good in this life not only, but in that which is to come, to an extent corresponding with the influence which education may exert upon independent mind. In order, then, most successfully to carry forward the great work of intellectual and moral culture, and to secure to man the fullest benefits of education in the present life, and in that higher mode of being which awaits him in the future, we have only to acquaint him with the laws by which embodied mind is governed, and to induce him to yield a ready, cheerful, and uniform obedience to those laws. We shall therefore devote the following pages to an inquiry into the laws which must be observed by embodied mind in order to render it the fittest possible instrument for discovering, applying, and obeying the laws under which G.o.d has placed the universe, which const.i.tutes the one great object of education, when considered in its widest and true sense.

All physiologists and philosophers regard the brain as the organ of the mind. Although it is not befitting here to give a particular description of this complicated organ, still it may be well further to premise that, by nearly universal consent, it is regarded as the immediate seat of the _intellectual_ faculties not only, but of the pa.s.sions and moral feelings of our nature, as well as of consciousness and every other mental act. It is also well established that the brain is the princ.i.p.al source of that nervous influence which is essential to vitality, and to the action of each and all of our bodily organs. As, then, its functions are the highest and most important in the animal economy, it becomes an object of paramount importance in education to discover the laws by which they are regulated, that by yielding obedience to them we may avoid the evils consequent on their violation.

Let no one suppose these evils are few or small; for, in the language of an eloquent writer, "the system of education which is generally pursued in the United States is unphilosophical in its elementary principles, ill adapted to the condition of man, practically mocks his necessities, and is intrinsically absurd. The high excellences of the present system, in other respects, are fully appreciated. Modern education has indeed achieved wonders. It has subst.i.tuted things for names, experiment for hypothesis, first principles for arbitrary rules. It has simplified processes, stripped knowledge of its abstraction and thrown it into visibility, made practical results rather than mystery the standard by which to measure the value of attainment, and facts rather than conjecture its circulating medium."[21]

[21] Report on Manual Labor, by Theodore D. Weld, 1833.

_A sound original const.i.tution_ may be regarded as the first condition of the healthy action of the brain; for, being a part of the animal economy, it is subject to the same general laws that govern the other bodily organs. When a healthy brain is transmitted to children, and their treatment from infancy is judicious and rational, its health becomes so firmly established that, in after life, its power of endurance will be greatly increased, and it will be enabled most effectually to ward off the insidious attacks of disease. On the other hand, where this organ has either inherited deficiencies and imperfections, or where they have been subsequently induced by early mismanagement, it becomes peculiarly susceptible, and frequently yields to the slightest attacks. The most eminent physiologists of the age concur in the opinion that, of all the causes which predispose to nervous and mental disease, the transmission of hereditary tendency from parents to children is the most powerful, producing, as it does, in the children, an unusual liability to those maladies under which their parents have labored.

When both parents are descended from tainted families, their progeny, as a matter of course, will be more deeply affected than where one of them is from a pure stock. This sufficiently accounts for the fact that hereditary predisposition is a more common cause of nervous disease in those circles that intermarry much with each other than where a wider choice is exercised. Fortunately, such is the const.i.tution of society in this country, that there are fewer evils of this kind among us than are manifest in many of the European states, where intermarriages are restricted to persons of the same rank, as has already been ill.u.s.trated by reference to the grandees of Spain, who have become a race of dwarfs intellectually as well as physically. But even in this country there are painful ill.u.s.trations of the truth of the popular belief that when cousins intermarry their offspring are liable to be idiotic. The command of G.o.d not to marry within certain degrees of consanguinity is, then, in accordance with the organic laws of our being, and the wisdom of the prohibition is abundantly confirmed by observation.

What was said of hereditary transmission in the second chapter of this work applies here with increased force. It is of the highest possible importance that this subject should receive the especial attention of every parent, and of all who may hereafter sustain the parental relation; for posterity, to the latest generations, will be affected by the laws of hereditary transmission, whether those laws are understood and obeyed or not. The importance of this subject, already inconceivably vast, becomes infinitely momentous in view of the probability that the evils under consideration are not confined to this life, but must, from the nature of the case, continue to be felt while mind endures.

Unfortunately, it is not merely as a cause of disease that hereditary predisposition is to be dreaded. The obstacles which it throws in the way of permanent recovery are even more formidable, and can never be entirely removed. Safety is to be found only in avoiding the perpetuation of the mischief. When, therefore, two persons, each naturally of an excitable and delicate nervous temperament, choose to unite for life, they have themselves to blame for the concentrated influence of similar tendencies in destroying the health of their offspring, and subjecting them to all the miseries of nervous disease, melancholy, or madness.

There is another consideration that should be noticed here: it is this.

Even where no hereditary defect exists, the state of the mother during pregnancy has an influence on the mental character and health of the offspring, of which even _few parents_ have any adequate conception. "It is often in the maternal womb that we are to look for the true cause not only of imbecility, but of the different kinds of mania. During the agitated periods of the French Revolution, many ladies then pregnant, and whose minds were kept constantly on the stretch by the anxiety and alarm inseparable from the epoch in which they lived, and whose nervous systems were thereby rendered irritable in the highest degree compatible with sanity, were afterward delivered of infants whose brains and nervous systems had been affected to such a degree by the state of their parent, that, in future life, as children they were subject to spasms, convulsions, and other nervous affections, and in youth to imbecility or madness, almost without any exciting cause."[22]

[22] The testimony of M. Esquirol, whose talent, general accuracy, and extensive experience give great weight to all his well-considered opinions, quoted, also, and confirmed by the Physician Extraordinary to the Queen in Scotland, and consulting Physician to the King and Queen of the Belgians.

The same eminent author has recorded the following fact, ill.u.s.trating the extent to which the temporary state of the mother, during gestation, may influence the _whole future life of the child_. A pregnant woman, otherwise healthy, was greatly alarmed and terrified by the threats of her husband when in a state of intoxication. She was afterward delivered, at the proper time, of a very delicate child, which was so much affected by its mother's agitation that, up to the age of eighteen, it continued subject to panic terrors, and then became completely maniacal.

Many ill.u.s.trative instances might be quoted from medical writers in this and other countries. The author might also refer to cases that have fallen under his own observation.

Dr. Caldwell, too, an able and philanthropic advocate of an improved system of physical, intellectual, and moral education in this country, is very urgent in enforcing rational care, during the period of gestation, on the part of every mother who values the future health and happiness of her offspring. Among other things, he insists on mothers taking more active exercise in the open air than they usually do. He also cautions them against allowing a feeling of false delicacy to keep them confined in their rooms for weeks and months together. At such times especially the mind ought to be kept free from gloom or anxiety, and in that state of cheerful activity which results from the proper exercise of the intellect, and especially of the moral and social feelings.

But if seclusion and depression be hurtful to the unborn progeny, surely thoughtless dissipation and late hours, dancing and waltzing, together with irritability of temper and peevishness of disposition, can not be less injurious. Every female that is about to become a mother should treasure up the remark of that sensible lady, the Margravine of Ans.p.a.ch, who says, "when a female is likely to become a mother, she ought to be doubly careful of her temper, and, in particular, to indulge no ideas that are not cheerful and no sentiments that are not kind. Such is the connection between the mind and the body, that the features of the face are moulded commonly into an expression of the internal disposition; and is it not natural to think that an infant, before it is born, may be affected by the temper of its mother?" If these things are true--and they are as well authenticated as any physiological facts are or can be--then not only _mothers_, but all with whom they a.s.sociate, and especially _fathers_, are interested in knowing these important physiological laws; and they should aim, from the very beginning, so to observe them as to secure to posterity, physically and mentally, the full benefits that are connected with cheerful obedience.

_A due supply of properly oxygenated blood_ is another condition upon which the healthy action of the brain depends. Although it may not be easy to perceive the effects of slight differences in the quality of the blood, still, when these differences exist in a considerable degree, the effects are too obvious to be overlooked. Withdraw entirely the stimulus of arterial blood, and the brain ceases to act, and sensibility and consciousness become extinct. When carbonic acid gas is inhaled, the blood circulating through the lungs does not undergo that process of oxygenation which is essential to life, as has been explained in a preceding chapter. As the venous blood in this unchanged state is unfit to excite or sustain the action of the brain, the mental functions become impaired, and death speedily ensues, as in the case of a number of persons breathing a portion of confined air, or inhaling the fumes of charcoal. On the other hand, if oxygen gas be inhaled instead of common air, the blood becomes too much oxygenated, and, as a consequence, the brain is unduly stimulated, and an intensity of action bordering on inflammation takes place, which also soon terminates in death.

These are extreme cases, I admit; but their consequences are equally remarkable and fatal. The slighter variations in the state of the blood produce equally sure, though less palpable effects. Whenever its vitality is impaired by breathing an atmosphere so vitiated as not to produce the proper degree of oxygenation, the blood can only afford an imperfect stimulus to the brain. As a necessary consequence, languor and inactivity of the mental and nervous functions ensue, and a tendency to headache, fainting, or hysteria makes its appearance. This is seen every day in the listlessness and apathy prevalent in crowded and ill-ventilated school-rooms, and in the headaches and liability to fainting which are so sure to attack persons of a delicate habit, in the contaminated atmospheres of crowded theaters, churches, and a.s.semblies of whatever kind. The same effects, although less strikingly apparent, are perhaps more permanently felt by the inmates of cotton manufactories and public hospitals, who are noted for being irritable and sensitive.

The languor and nervous debility consequent on confinement in ill-ventilated apartments, or in air vitiated by the breath of many people, are neither more nor less than minor degrees of the process of poisoning, which was particularly explained in the preceding chapter, while treating upon the philosophy of respiration.

That it is not real debility which produces these effects, is apparent from the fact, that egress to the open air almost instantly restores activity and vigor to both mind and body, unless the exposure has been very long. There is an interesting but fearful ill.u.s.tration of the truth of this statement at the 96th page of this work, to which I beg leave to refer. Where the exposure has been very long continued, more time is of course required to re-establish the exhausted powers of the brain.

Indeed, we may not, in such cases, hope for complete recovery; for when persons remain several hours a day in a vitiated atmosphere, for weeks and months together, both mind and body become permanently diseased. It is well known to every person who has given attention to the subject, that hitherto this has been the condition of _public schools_, generally, in every part of the United States, and throughout the civilized world. This has, perhaps, tended more than all other causes combined, to render the profession of teaching disreputable, and to const.i.tute the very name of schoolmaster, or pedagogue, a hissing and a by-word. And why is this? I can account for it in but one way. The school teacher is subject to the _same organic laws as other men_; and, either on account of the ignorance or parsimony of his employers, he has been shut up with _their_ children several hours a day, in narrow and ill-ventilated apartments, where, whatever else they may have done, their princ.i.p.al business has of necessity been _to poison one another to death_. And, as if not satisfied with this, when the teacher has ruined his health in our employment, and become a mere wreck, physically and mentally, _we despise him_. This is a double injustice, and _is_ adding insult to injury. And the consequences are hardly less fatal to the children. The situation of the majority of our schools, when viewed in connection with the physiological laws already explained, sufficiently accounts for that irritability, listlessness, and languor which have been so often observed in both teachers and pupils. Both irritability of the nervous system and dullness of the intellect are unquestionably the direct and necessary result of a want of pure air. The vital energies of the pupils are thus prostrated, and they become not only restless and _indisposed to study_, but absolutely _incapable of studying_. Their minds hence wander, and they unavoidably seek relief in mischievous and disorderly conduct. This doubly provokes the already exasperated teacher, who can hardly look with complaisance upon good behavior, and who, from a like cause, is in the same irritable condition of both body and mind with themselves. He, too, must needs give vent to his irascible feelings some how. And what way is more natural, under such circ.u.mstances, than to resort to the use of the ferule, the rod, and the strap! We have already referred to a case, in which formerly fever constantly prevailed, but where disease disappeared altogether upon the introduction of _pure air_. Let the same prudential course be adopted in our schools, in connection with other appropriate means, and we shall readily see the superiority of the natural stimulus of oxygen over the artificial sedative of the rod.

_The regular and systematic exercise of the functions of the brain_ is another condition upon which its healthy action depends. The brain is an organized part, and is subject to precisely the same laws of exercise that the other bodily organs are. If it is doomed to inactivity, its health decays, and the mental operations and feelings, as a necessary consequence, become dull, feeble, and slow. But let it be duly exercised after regular intervals of repose, and the mind acquires activity and strength. Too severe or too protracted exercise of the brain is as great a violation of the organic law just stated as inactivity is, and is sometimes productive of the most fearful consequences. By over-tasking this organ, either in the force or duration of its activity, its functions become impaired, and irritability and disease take the place of health and vigor.

So important is the law under consideration, and so essential to the health of the brain and to the welfare of man, that I deem it advisable to explain more particularly the consequences of both inadequate and excessive exercise.

We have seen that by disuse the muscles become emaciated and the bones soften. The blood-vessels, in like manner, become obliterated, and the nerves lose their characteristic structure. _The brain is no exception to this general rule._ Its tone is impaired by permanent inactivity, and it becomes less fit to manifest the mental powers with readiness and energy. Nor will this surprise any reflecting person, who considers that the brain, as a part of the same animal system, is nourished by the same blood, and regulated by the same vital laws as the muscles, bones, arteries, and nerves.