I admire, said I, your courage, my brave Jack, but it shall not be tried on this occasion. Neither lions, serpents, nor men are there, yet the danger still exists: how would my young hero acquit himself, when on entering the aperture he should feel his respiration totally cease?
Jack.—Not be able to breathe! and why not?
Fritz.—Because the air is mephitic, that is, foul, and therefore unfit for breathing in, and those who are exposed to it must of course be suffocated. But in what manner, father, is this air corrupted?
Father.—In different ways: for example, when it is replete with noxious vapours, or when it contains too many igneous or inflammable particles, or when it is too heavy or dense, as fixed air is; but in general, when it merely loses its elasticity, it no longer passes freely into the lungs; respiration is then stopped, and suffocation speedily ensues, because air is indispensable to life and the circulation of the blood.
Jack.—Then all to be done is to be off quickly when one feels a stoppage of breath.
Father.—This is certainly the natural course when it can be taken; but the attack usually begins by a vertigo or dizziness of the head, so violent as to intercept motion, which is followed by an insurmountable oppression; efforts are made to breathe, fainting follows, and without speedy help, a sudden death takes place.
Fritz.—What assistance can be administered?
Father.—The first thing to be done is to remove the person so affected to pure fresh air, and to throw cold water over his body; he must then be well dried, and afterwards rubbed with warm cloths; vital air must be infused, or tobacco-smoke thrown up; in short, he must be treated like a drowned person till signs of re-animation appear, which is not always the result.
Fritz.—But why do you think, father, the air in this cavern is mephitic, as you term it, or dangerous to breathe in?
Father.—All air confined and wholly separated from that of the atmosphere, gradually loses its elasticity, and can no longer pass through the lungs: in this state it generates injurious qualities that interrupt the process of respiration. It is in this act that the atmospheric air diffused around us, unites intimately with the blood, to which it communicates one of its most essential parts, called vital air, for without it life cannot be supported. This air failing, respiration ceases, and death succeeds in a few minutes: the consequence is similar when this air is impregnated too abundantly with injurious parts.