Mark the following particulars: 1. The quantity of air breathed by forty-five persons in three hours, according to the data just given, is 3375 cubic feet. 2. Air once respired will not sustain animal life. 3. The school-room was estimated to possess a capacity of 3360 cubic feet—fifteen feet less than is necessary to sustain healthy respiration. 4. Were forty-five persons whose lungs possess the estimated capacity placed in an air-tight room of the preceding dimensions, and could they breathe pure air till it was all once respired, and then enter upon its second respiration, they would all die with the apoplexy before the expiration of a three hours' session.

From the nature of the case, these conditions can not conveniently be fulfilled. But numerous instances of fearful approximation exist. We have no air-tight houses. But in our latitude, comfort requires that rooms which are to be occupied by children in the winter season, be made very close. The dimensions of rooms are, moreover, frequently narrowed, that the warm breath may lessen the amount of fuel necessary to preserve a comfortable temperature. It is true, on the other hand, that the quantity of air which children breathe is somewhat less than I have estimated. But the derangement resulting from breathing impure air, in their case, is greater than in the case of adults whose constitutions are matured, and who are hence less susceptible of injury. It is also true in many schools that the number occupying a room of the dimensions supposed is considerably greater than I have estimated. Moreover, in many instances, a great proportion of the larger scholars will respire the estimated quantity of air.

Again, all the air in a room is not respired once before a portion of it is breathed the second, or even the third and fourth time. The atmosphere is not suddenly changed from purity to impurity—from a healthful to an infectious state. Were it so, the change, being more perceptible, would be seen and felt too, and a remedy would be sought and applied. But because the change is gradual, it is not the less fearful in its consequences. In a room occupied by forty-five persons, the first minute, thirty-two thousand four hundred cubic inches of air impart their entire vitality to sustain animal life, and, mingling with the atmosphere of the room, proportionately deteriorate the whole mass. Thus are abundantly sown in early life the fruitful seeds of disease and premature death.

This detail shows conclusively sufficient cause for that uneasy, listless state of feeling which is so prevalent in crowded school-rooms. It explains why children that are amiable at home are mischievous in school, and why those that are troublesome at home are frequently well-nigh uncontrollable in school. It discloses the true cause why so many teachers who are justly considered both pleasant and amiable in the ordinary domestic and social relations, are obnoxious in the school-room, being there habitually sour and fretful. The ever-active children are disqualified for study, and engage in mischief as their only alternative. On the other hand, the irritable teacher, who can hardly look with complaisance upon good behavior, is disposed to magnify the most trifling departure from the rules of propriety. The scholars are continually becoming more ungovernable, and the teacher more unfit to govern them. Week after week they become less and less attached to him, and he, in turn, becomes less interested in them.

This detail explains, also, why so many children are unable to attend school at all, or become unwell so soon after commencing to attend, when their health is sufficient to engage in other pursuits. The number of scholars answering this description is greater than most persons are aware of. In one district that I visited a few years ago in the State of New York, it was acknowledged by competent judges to be emphatically true in the case of not less than twenty-five scholars. Indeed, in that same district, the health of more than one hundred scholars was materially injured every year in consequence of occupying an old and partially-decayed house, of too narrow dimensions, with very limited facilities for ventilation. The evil, even after the cause was made known, was suffered to exist for years, although the district was worth more than three hundred thousand dollars. And what was true[13] of this school, is now, with a few variations, true in the case of scores, if not hundreds of schools with which I am acquainted, from far-famed New England to the Valley of the Mississippi.

This detail likewise explains why the business of teaching has acquired, and justly too, the reputation of being unhealthy. There is, however, no reason why the health of either teacher or pupils should sooner fail in a well-regulated school, taught in a house properly constructed, and suitably warmed and ventilated, than in almost any other business. If this statement were not true, an unanswerable argument might be framed against the very existence of schools; and it might clearly be shown that it is policy, nay, duty, to close at once and forever the four thousand school-houses of Michigan, and the hundred thousand of the nation, and leave the rising generation to perish for lack of knowledge. But our condition in this respect is not hopeless. The evil in question may be effectually remedied by enlarging the house, or, which is easier, cheaper, and more effectual, by frequent and thorough ventilation. It would be well, however, to unite the two methods.

In the winter of 1841-2, I visited a school in which the magnitude of the evil under consideration was clearly developed. Five of the citizens of the district attended me in my visit to the school. We arrived at the school-house about the middle of the afternoon. It was a close, new house, eighteen by twenty-four feet on the ground—two feet less in one of its dimensions than the house concerning which the preceding calculation is made. There were present forty-three scholars, the teacher, five patrons, and myself, making fifty in all. Immediately after entering the school-house, one of the trustees remarked to me, "I believe our school-house is too tight to be healthy." I made no reply, but secretly resolved that I would sacrifice my comfort for the remainder of the afternoon, and hazard my health, and my life even, to test the accuracy of the opinions I had entertained on this important subject. I marked the uneasiness and dullness of all present, and especially of the patrons, who had been accustomed to breathe a purer atmosphere. School continued an hour and a half, at the close of which I was invited to make some remarks. I arose to do so, but was unable to proceed till I opened the outer door, and snuffed a few times the purer air without. When I had partially recovered my wonted vigor, I observed with delight the renovating influence of the current of air that entered the door, mingling with and gradually displacing the fluid poison that filled the room, and was about to do the work of death. It seemed as though I was standing at the mouth of a huge sepulcher, in which the dead were being restored to life. After a short pause, I proceeded with a few remarks, chiefly, however, on the subject of respiration and ventilation. The trustees, who had just tested their accuracy and bearing upon their comfort and health, resolved immediately to provide for ventilation according to the suggestions in the article on school-houses in the last chapter of this work.

Before leaving the house on that occasion, I was informed an evening meeting had been attended there the preceding week, which they were obliged to dismiss before the ordinary exercises were concluded, because, as they said, "We all got sick, and the candles went almost out." Little did they realize, probably, that the light of life became just as nearly extinct as did the candles. Had they remained there a little longer, both would have gone out together, and there would have been reacted the memorable tragedy of the Black Hole in Calcutta, into which were thrust a garrison of one hundred and forty-six persons, one hundred and twenty-three of whom perished miserably in a few hours, being suffocated by the confined air.

What has been said in the preceding pages on the philosophy of respiration was first given to the public nearly ten years ago, in a report of the author's in the State of New York. He has since seen the same sentiments inculcated by many of our most eminent practical educators, some of whom had written upon the subject at an earlier date. Allen and Pepy showed by experiment that air which has been once breathed contains eight and a half per cent. of carbonic acid, and that no continuance of the respiration of the same air could make it take up more than ten per cent. Air, then, when once respired, has taken up more than four fifths of the amount of this noxious gas that it can be made to by any number of breathings.

Dr. Clark, in his work on Consumption, remarks as follows: "Were I to select two circumstances which influence the health, especially during the growth of the body, more than others, and concerning which the public, ignorant at present, ought to be well informed, they would be the proper adaptation of food to difference of age and constitution, and the constant supply of pure air for respiration." Dr. William A. Alcott, who has given especial attention to this subject, after quoting the preceding remark of Dr. Clark, adds: "We believe this is the opinion of all medical men who have studied the constitution of man, and its relation to outward objects."