P. J. Higgins

“ Being exceedingly light, they float in the air, and are inhaled, lodging in the throat, trachea, and even deep in the lungs. It is not pleasant to contemplate the fact that we inhale minute portions of each other's bodies, but it is true nevertheless. ”

“ The quantity thrown off in breathing is very much increased—often nearly doubled—during active digestion. As the fullest meal is taken at dinner, and digestion is most active soon after, it follows that the exhalation of carbonic-acid gas is greatest during the early part of the afternoon, and therefore during this time ventilation needs more attention. Of all the impurities found in the school-room, this is vastly the largest in amount, and popularly considered the most important. It is once and a half as heavy as air. ”

“ It is the difference in temperature that produces a draught up a flue or chimney when a fire is lighted below; for the products of combustion have a very much higher temperature (several hundred degrees Fahr.) than the surrounding atmosphere. Being so much warmer, they are lighter in consequence (as will be explained presently) , and therefore have a constant tendency to ascend—being compelled by the force of gravity—till, after cooling little by little, they reach a layer of their own temperature. ”

“ Air becomes vitiated for breathing purposes by holding in solution other gases or substances whose presence interferes with the appropriation of oxygen by the animal, or, being themselves absorbed, exert a toxic influence upon the vital fluid and tissues of the body. Hence to secure an adequate supply of fresh air, and the removal of impurities that accumulate therein, are the objects of ventilation. ”

“ VENTILATION is the supply of fresh air to an apartment, and the removal of impure or vitiated air therefrom. An adequate supply of free oxygen is absolutely necessary to animal life; and, the higher we ascend in the scale of that life, the greater the quantity of oxygen consumed, and the more urgent the necessity for its consumption. ”

“ In this paper school-room ventilation only will be considered.
A full-grown person breathes on an average about twenty times per minute, and takes in over twenty cubic inches of air at each inspiration. Boys and girls inspire somewhat less than twenty cubic inches, but breathe more rapidly than an adult—say twenty-five times per minute. In five minutes each will breathe over a cubic foot of air, and in a two-hours session nearly twenty-five cubic feet: so that, in a school of forty pupils, one thousand cubic feet will be inhaled every two hours. ”

“ The drier the air, the more rapidly are the liquids of the body evaporated, and digestion and assimilation carried on, the more nervous is the temperament, and the more rapid the development. Generally speaking, the air is much drier in the United States than in Europe. ”

“ The animal exhalations will fill the room from the ceiling to the level of the top of the communicating door, and there remain. It would cost but a trifle to have one or two ventilators put in the ceiling of a school-room where there are none in the walls; and school directors could not make a better investment of the money. Children will not study, and can not be persuaded or compelled to study diligently, in the foul and stifling air of a crowded and wretchedly ventilated room. ”

“ When the outside air is the warmer, and per consequence the lighter, as on a very warm summer day, the direction of the currents, other things being the same, will be reversed—the fresh air coming in above, and the cool air within escaping below. But, owing to the large amount of heat radiated from the pupils—the normal temperature of the human body averaging 37·5° Cent., or 99° Fahr.—the lighter air is nearly always within. Therefore, if on the sheltered side a window is lowered at the top, or on any side if the air be calm, the foul air will escape above it ”

“ In this way the currents that are likely to blow on the children's shoulders when the windows are raised are avoided, a matter of importance; for a draught of cold air, blowing upon the shoulders from behind, arrests the action of the skin—probably through the spinal sensory nerves—and causes what is commonly known as a "cold." Even when windows are lowered at the top, draughts will occasionally blow upon the pupils; and, the lower the windows are set in the wall, the stronger and more uncomfortable and injurious is the draught. ”

“ Again, the warmer the day, the less the difference between the temperature of the inside and the outside air; hence the buoyancy of the inside air is less, and consequently the ventilation not so effective; so that more attention and greater facilities must be afforded it. Ventilators should never be placed in the hall; here they do but little good. The doors leading from the hall to the rooms are usually closed, and, even if open, the buoyancy of the air as a factor in ventilation is nearly eliminated ”

“ The frequent cough and occasional sneeze heard among the audience in theatre, hall, or church, are provoked by the inhalation of fine dust suspended in the air, and might be prevented by careful sweeping and dusting after occupancy. ”

“ In a stove-pipe the elbows should be as few in number as possible, and rounded rather than acute; for a sharp or abrupt bend materially diminishes the velocity of the draught. Two or more pipes opening into the same chimney should have separate flues; when they open into the same flue, the pipe that draws best will interfere with the draught in the others, and set up downward currents.
The air consumed by combustion escapes by the chimney, and tends to create a vacuum in the room ”

“ But, fortunately, the disease is comparatively infrequent under the age of fifteen, and added to this is the protecting influence of the active exercise in the open air usually indulged in by school-children. It is upon the teachers that its blighting effects are most apparent, as they are predisposed by age, they neglect exercise in the open air, and their mental labor is severe, and worry of mind exhausting. ”

“ As children drink much water, they exhale much aqueous vapor—the sweat-glands and capillary circulation being more active than in the adult say to the amount of half a pint each, more or less, during school-hours. ”

“ It is claimed by some physicists that carbonic oxide will make its way through heated iron, and thus escape through the sides of the stove, but the quantity given out in this way—if, indeed, any is so given out, of which there is a reasonable doubt—must be so small that it is practically of no account, while quantities large enough to be decidedly injurious may issue through the door and other openings. ”

“ In diphtheria, scarlatina, small-pox, measles, etc., these epithelial scales come off in vastly greater quantities than in health, carrying with them, in greater or less virulence, the peculiar infection in the body whence they have arisen. The greater their number and the more favorable the nidus in which they become deposited, the more likely they are to become transplanted as primary centers of infection. ”

“ This is the chief reason why our children are less repressible, livelier, and more nervous and precocious than those of Europe. Another reason is, that we use here more animal food, which is far more stimulating both to body and mind than vegetable. On the other hand, too dry an atmosphere is unhealthy. ”

“ It may be safely asserted that in a majority of our schools the ventilation is insufficient, or not properly attended to, either on account of lack of knowledge or attention on the part of the teacher, or the defective construction of the building. ”

“ Of late years, owing to the large amount of blackboard work done in schools, particularly in the primary departments, chalk-dust floats in large quantities in the air whenever the erasers are used. The particles of chalk-dust are comparatively large in size. ”