But bad food and bad housing are not the only enemies of the workman's health. The nature of his daily toil and the conditions under which it is performed are often against him. Even ventilation becomes important when one has to spend ten, eleven, or twelve hours a day in one room, and yet this is almost entirely neglected.

In 1908 a special officer was appointed in New York State to make tests of the atmospheric conditions in places of business. One hundred and thirty-six factories were examined, and in some printing establishments as many as forty parts of carbonic-acid gas (CO2) in ten thousand volumes of air were found, though a legal limit of twelve is recommended. One cigar factory, with windows partly open,had eighty such parts. The following table will exhibit the results of this investigation.[66]

Parts of CO2 in
10,000 vols. air		 5-1213-2021-2526-3031-4042-6065-7075-80
Factories in
each class		 82 166 80 67 30 8 3 3

Sometimes the exigencies of the trade require that there should be no draft, as in the handling of carbon filaments for incandescent lamps, and then the conditions of the atmosphere become acutely unhealthy. In addition, in some of the rooms numerous bunsen burners are always lighted and all currents of air carefully excluded to prevent their flickering.[67]

Elsewhere, the process of manufacture often vitiates the air, as the "blow-over" in bottle shops. "In some factories, at times the air is so full of this floating glass that the hair is whitened by merely passing through the room. It sticks to the perspiration on the face and arms of the boys and men and becomes a source of considerable irritation. Getting into the eyes it is especially troublesome" (l. c., p. 66). Something similar occurs in etching glass by a sand-blast. Unless a hood and exhaust are provided, a pressure of from fifty to ninety pounds scatters fine sand and glass dust through the air and is breathed in by the operator (l. c., p. 440). Even worse, however, is the acid etching, as the fumes of hydrochloric acid cause severe irritation to the throat and lungs (l. c., p. 442).

Even when there is no such irritant in the air as just mentioned, extreme differences in temperature between the work-room and the outside, or between various parts of the shop, may be a source of serious danger to health. In the glass industry, many persons have to work in temperatures ranging from ninety to one hundred and forty degrees, and as high as fifty degrees above the outside air (l. c., p. 75). Industries where an artificial humidity is required, such as silk, cotton and flax spinning, are likely to induce rheumatism, pleurisy, etc. After working ten hours in a room filled with live steam to prevent breaking of threads, to pass into a New England blizzard is apt to produce serious results. The boys in bottle-making shops are obliged to pass continually from a temperature of 140 degrees at the "glory-hole" to one of 90 degrees or less in other parts (l. c., pp. 49ff.).

And even if conditions of atmosphere and ventilation are good, the mere fact of continuing work for thirteen hours seven days a week tells seriously upon the physical endurance of the strongest.[68] When night work is required in addition to the day's labor, as in the glass industry, the consequences are likely to be worse, especially where children are concerned.[69] Night work frequently means a presence in the factory of at least twenty hours out of the twenty-four. "During the course of the investigation there were found two cases of recent death, both children, which could be directly attributed to exhaustion due to double-shift work in the furnace room" (l. c., p. 122).

In the clothing trade, "some piece and task-workers reported that they commonly worked seventy-two and even seventy-eight hours a week during busy periods" (l. c., p. 115). "There were instances where women said they worked from 6 or 7 o'clock in the morning to 9, 10, or 11 o'clock at night" (l. c., p. 241). For store girls, "thirteen and one-half hours on Saturday is not only excessive but works considerable hardship."[70] "One girl worked 24½ hours at one stretch with but two half-hour intermissions for meals.... Four girls working in one establishment on the 'night force' one day for each week reported their 'longest day's' labor as 16¾, 20¼, 22½, 24¼ hours" (l. c., p. 205). On the elevated railways in Chicago, at the time of the investigation, 1907-08, women worked for 80½ hours a week (l. c., p. 208).

When the business requires the maintaining of practically one position all day, whether standing or sitting, such long hours are bound to have a bad physical effect. This is the case, for example, in department stores (l. c., p. 178); in the glass industry where many growing boys are cramped before the furnace holes all day long;[71] in many processes in the manufacture of incandescent lamps (l. c., p. 482-483); and numerous other occupations.