Dust.—Every species of dust must prove injurious. Workers in those factories where tools are ground and polished soon die of pulmonary disease. The dust of cotton and woollen factories, that of the street, and that which is constantly rising from our carpets, are all mischievous. M. Benoiston found among cotton-spinners the annual mortality from consumption to be 18 in a thousand; among coal-men, 41; among those breathing an atmosphere charged with mineral dust, 30, and with dust from animal matter, as hair, wool, bristles, feathers, 54 per thousand: of these last the greatest mortality was among workers in feathers; least among workers in wool. The average liability to consumption among persons breathing the kinds of dust named was 24 per thousand, or 2.40 per cent. In a community where many flints were made, there was great mortality from consumption, the average length of life being only 19 years.
Gases.—Among the poisonous gases which infest our atmosphere, carbonic acid deserves special consideration. The principal result of all respiration and combustion, it exists in minute quantities everywhere, but when it accumulates to the extent of one or two per cent, it seriously compromises health. I have seen the last half of an eloquent sermon entirely lost upon the congregation; carbonic acid had so accumulated that it operated like a moderate dose of opium. No peroration would arouse them. Nothing but open windows could start life's currents. In lectures before lyceums, I often have a quarrel with the managers about ventilation. There is, even among the more intelligent, a strange indifference to the subject.
The following fact graphically illustrates the influence of carbonic acid on human life.
A young Frenchman, M. Deal, finding his hopes of cutting a figure in the world rather dubious, resolved to commit suicide; but that he might not leave the world without producing a sensation and flourishing in the newspapers, he resolved to kill himself with carbonic acid. So, shutting himself up in a close room, he succeeded in his purpose, leaving to the world the following account, which was found near his dead body, the next morning.
"I have thought it useful, in the interest of science, to make known the effects of charcoal upon man. I place a lamp, a candle, and a watch on my table, and commence the ceremony.
"It is a quarter past ten. I have just lighted the stove; the charcoal burns feebly.
"Twenty minutes past ten. The pulse is calm, and beats at its usual rate.
"Thirty minutes past ten. A thick vapor gradually fills the room; the candle is nearly extinguished; I begin to feel a violent headache; my eyes fill with tears; I feel a general sense of discomfort; the pulse is agitated.
"Forty minutes past ten. My candle has gone out; the lamp still burns; the veins at my temple throb as if they would burst; I feel very sleepy; I suffer horribly in the stomach; my pulse is at eighty.
"Fifty minutes past ten. I am almost stifled; strange ideas assail me.... I can scarcely breathe.... I shall not go far.... There are symptoms of madness....