let them be introduced into all other counties. Men from any of the professions will be found, who would gladly aid the Superintendent and teachers on such an occasion, and men not belonging to the professions, farmers, mechanics, merchants and others, can easily be induced to take part in the exercises, who may utter sentiments which the children and youth will carry with them through life.

The influence which the Superintendents are exerting to induce the school officers to make the necessary repairs upon their school-houses and all that pertains to them, should not be passed unnoticed. Improvements have already been completed upon some houses, and many promises given that others shall be made during the present year.

The school-houses in many districts are in a dilapidated condition, the grounds, small as they are, remain unfenced, and the whole appearance is unsightly, and extremely forbidding. This condition of things is suffered to remain, year after year, not because of the poverty of the people, nor because they are unwilling to be at the expense of making the necessary improvements, but simply from a want of interest. Their attention has not been called to the matter with sufficient earnestness to lead them to act. The Superintendent will be a constant monitor calling for the performance of neglected duties. With but little extra effort on the part of the proper officers, an entire and speedy-change could be effected in the appearance of the many school-houses that are now so repulsive. With the money and labor which could be easily secured, they might be rendered attractive and beautiful. We hope to see these changes speedily effected, and the school rooms supplied with blackboards, charts, globes and all those appliances necessary for the successful prosecution of the teacher's work.

From the reports of the various Superintendents, it appears that but little, if any, attention is given to the subject of ventilation. No provision whatever has been made to furnish a supply of pure air to the pupils in the densely crowded rooms. On the contrary, the great effort seems to have been, to pre

vent any change of air, and the effort has proved remarkably successful.

Having, by request, prepared a paper upon this subject, for the Convention of County Superintendents, the farther request was made, that it be inserted in this report. Although the discussion is a lengthy one for such a document, the importance of the subject would seem to demand that we should comply with the request.

VENTILATION.

The objects of ventilation are, to supply pure air, of the proper temperature, and to remove that which has become impure. The demand for a constant supply of fresh air, arises from the wants of our physical natures.

Air is the great purifier of the blood.

The blood, as found

in the right side of the heart, is a compound of three kinds of matter:

1st. The part of the blood which has been returned from the extremities.

2d. The worn out or rejected particles of the various tissues of the body.

3d. The chyle which has entered the veins through the lacteals.

This compound is in a large degree charged with carbonic acid and water. In this condition it is entirely unfit to supply the wants of the body, and if returned to the extremities, it would create disturbance and general derangement. It must first be sent to the lungs, and there be brought in contact with the air, which takes place in the air cells.

By this contact the blool undergoes an entire change. The carbonic acid and water are liberated; oxygen from the air is absorbed by the blood, changing the dark purple compound to a bright scarlet. The blood is thus relieved of the dead and useless portion and supplied with living particles, ready to be carried back to supply the constant waste of the system.

To secure the complete purification of the blood, pure air is

required. Hence, air that has once been breathed, should never be inhaled a second time, for it is, to a considerable extent, saturated with water, and contains a large amount of carbonic acid. In this condition, it is unfit to be received into the lungs.

Physiologists tell us that when air contains more than three and one-half per cent. of carbonic acid, it cannot be inhaled without detriment, and yet more than four per cent. of this acid is added to the volume of air inhaled at each respiration.

A two-fold evil arises from breathing air thus vitiated. First, the blood which has reached the lungs charged with carbonic acid and water, must be returned to the extremities but partially cleansed, as but a part of the impurities can be removed, for the impure air received has its capacity for holding carbonic acid and water greatly diminished. This is seen in the sponge; when partially filled with water, it will take less and receive it more slowly than when all the water has been expelled from it. So the air, partly saturated, will receive less of the vitiating properties of the blood than when pure, and as a consequence the blood must be returned to the system in a condition to poison, rather than to build up and give renewed life.

2d. The excess of carbonic acid in the air, acts as a poison upon the system. In pure carbonic acid, animal life cannot be sustained for an instant; and when the air is impregnated with this gas, to a considerable extent, the effects of breathing it are most manifest; dullness, stupor and dizziness are some of the milder symptoms; faintness, difficult breathing and insensibility, are among the graver effects.

The specific gravity of carbonic acid gas, is greater than that of air. Hence, when mingled with air, it sinks to the bottom. If carbonic acid gas, is in any way thrown into a tight room, it will at once sink to the floor and gradually fill up the room, displacing the air as surely as water would do it, if permitted to enter. Burning coals generate this gas with great rapidity. Place a vessel containing live coals in a tight room, and the room at once begins to be filled with this gas. If persons are

sleeping there, as soon as the room is filled to the hight of the bed, they will as speedily perish as if the room were to fill with water. Indeed, they would more surely and speedily perish, for water would doubtless arouse the sleepers and they might escape. But so stealthily does this gas creep over them, benumbing the senses, rendering unconscious its victims, while it steals away the life, that their destruction is sure.

With these few facts before us, we are prepared to examine the condition of our school rooms, when filled with pupils.

In usual respiration, the oxygen of about 720 cubic inches of air is consumed in one minute, by one person. The air that is expelled from the lungs, contains four or five per cent. of carbonic acid, yet we can breathe but three and one-half per cent. with impunity. It is found by experiment, that with the carbonic acid usually found in air, what is added by the respiration of one person, for one minute, is sufficient to render 1800 inches of air unfit to breathe. The impurities thrown off by the lungs by children, will not vary much from what adults would throw off in the same time. Although the capacity of the lungs in adults is greater than in children, the respirations are so much more frequent in childhood, as to make the amount of air breathed by each, vary but little. Besides the carbonic acid, there are large quantities of water thrown from the lungs constantly. This passes off in an invisible vapor, unless it is rendered visible by being condensed, by coming in contact with cold air, as it does in winter, when it becomes fog, and even snow and ice, if the temperature of the air be sufficiently low. Vapor is also arising from all parts of the body, by insensible perspiration. The skin is constantly active, throwing off or breathing out vapor, from its millions of little mouths, so that not less than 3600 cubic inches of air are saturated with vapor each minute. By the lungs and skin, nearly four cubic feet of air are rendered unfit to breathe, by each person every minute.

What then, must be the condition of our school rooms after they have been occupied but a single hour? If we should estimate the space in our school rooms and the number of chil

dren in them, we could get some idea of what the state of the atmosphere must be.

A room 20 feet by 30, and 10 feet high, would give more space than is usually found in school rooms. This gives a capacity of 6,000 cubic feet. As usually arranged, 100 pupils could conveniently be seated in the room. But let us take a less number. We will suppose but 75 to attend the school. These would in one minute vitiate 300 cubic feet of air. With this rate of consumption, in 20 minutes the entire volume of air in the room, would be so far consumed as to render every part entirely unfit to breathe, if each should have his four feet given him at each respiration.

But there are many parts of the room where the air remains comparatively fixed, and only a part of what is in the room reaches the lungs of the pupils, notwithstanding the currents and counter currents, which bring a part of the air to the pupils, which otherwise would never reach them; but while those portions in distant parts of the room have been making their way to these pupils, much of the air has been breathed over and over again; not that each pupil has been breathing over and over his own breath, but worse than that, for each has been breathing over the air expelled from the lungs of those sitting around, impregnated with all that is loathsome and revolting. Children are exceedingly fastidious about drinking from the same cup that others have used, nor does this fastidiousness diminish as children grow older. But we never think of what we are doing, while swallowing cubic foot after cubic foot of air, hot and foetid, just blown from the lungs of some beer-guzzling, whisky-soaked, tobacco-steeped biped called a man. It is well for us that our organs of vision are as obtuse as they are, for if we could see as clearly as by the use of a lens, what is floating in the air we are often breathing, we should be anxious to flee from ourselves, and surely from all others.

But the deleterious effects of what we breathe, are not destroyed because of blunted vision. Children in the school room