the stomach, and are frequently sallow and anæmic. A gradual tolerance may be established, and the danger is very slight if free ventilation is provided. When evolved in the open air, and hence largely diluted, it does not produce any injurious effects, except in very susceptible persons; indeed the people around Vesuvius told Doctor De Chaumont that the sulphur fumes are good for their health.

The Massachusetts Board of Health found that, in the straw-hat factories visited in Massachusetts, "the employees are exposed to the sulphur fumes only when the doors are opened for the removal of the stock; but they do not enter until the fumes have escaped or have been driven out." The men do not wear respirators in this or the other process of bleaching, which is done by immersion of the stock in a chemical water bath. The men who were interviewed state that "neither process causes anything more than a temporary irritation of the throat, and that many of them have worked in this department for many years."1

HYDROCHLORIC ACID.

Hydrochloric-acid vapors are evolved from alkali works and in the pickling process of galvanizing works or otherwise, and, apart from being destructive to vegetation around the immediate vicinity, are also very irritating, and even in small volumes may produce inflammation of the eyes and of the respiratory passages. In a more concentrated form they have produced caustic effects on the tips and edges of the tongue, ulcerations of the nasal wall and throat, bronchial catarrh, pneumonia, difficult breathing, and stupor. Lehmann considers the extreme limit to which these vapors may be contained in the air 1/10 of volume per 1,000, and relates a case where even 0.5 per 1,000 produced unpleasant symptoms in a robust man. Pettenkoffer,3 on the other hand, states that as much as I part per 1,000 can be borne by those accustomed to it. The workmen in galvanizing works are also subjected to fumes arising from the sal ammoniac thrown upon the molten zinc. These fumes are to some more insupportable than the acid fumes. Persons with bronchial troubles are often obliged to discontinue the work. In an investigation of three galvanizing establishments in Boston, the Massachusetts Board of Health found that in two the ventilation was efficient and the fumes were rapidly carried off. "The work

Report of the State Board of Health of Massachusetts upon the sanitary condition of factories, workshops, etc., Boston, 1907, p. 114.

2Lehmann: Archiv. fuer Hygiene, v. 1.

3 Cited by Harrington.

men in all three, about 60 in all, appeared to be in good health, and asserted that beyond sneezing and coughing at times they suffered no inconvenience or discomfort."

SULPHURIC AND NITRIC ACID.

The fumes of sulphuric and nitric acids probably produce similar effects. Eulenberg' believes, however, that the fumes of sulphuric acid produce no special bad effects, because they sink very readily and have a great affinity for the water in the air, so that they reach the system in a highly diluted form. He also points out that the nitrous fumes generated by contact of nitric acid with metals are more injurious, in that they produce a special predisposition to bronchitis, while pneumonia and diseases of the eye have also been attributed to these gases.

The workmen should be instructed to avoid the fumes as much as possible and to anoint the lips and nose within and without several times a day. Protection should be afforded by ample ventilation, and all processes involving the evolution of irritating or poisonous fumes should be carried on in the open air or in open sheds.

According to the Massachusetts Board of Health2 the corrosive acids are made in such a way that practically no fumes whatever escape, the work being inclosed from beginning to end. In one of the largest chemical factories in Massachusetts, where 300 men are employed, it is said that the workmen are exposed very little to poisonous or irritating fumes and dust or contact with poisonous or irritating substances. At certain points in the building acid fumes in considerable strength are constantly present, but at these points there is good overhead ventilation, and the workmen are rarely obliged to approach very near.

Among the products of the above-mentioned factories may be mentioned hydrochloric, sulphuric acid, nitric acid, acetic acid, ammonia, sodium sulphite, sodium sulphate, alum, potassium cyanide, ferrous sulphate, and other iron and sodium salts; also various salts of tin, arsenic, antimony, zinc, copper, etc.

AMMONIA.

Ammonia rarely causes any serious disturbance, except a temporary irritation of the respiratory tract, unless present in very large volumes. The amount which may be present, according to Lehmann, should not

Eulenberg, Gewerbehygiene, p. 143.

2Report of the State Board of Health of Massachusetts upon sanitary conditions of factories, workshops, etc., 1907, p. 103.

exceed 0.5 per 1,000. A large volume has been known to cause inflammation of the eyes and bronchial catarrh, while still greater concentrations, which fortunately are rare, may produce difficult breathing and emphysema.

CHLORINE GAS

Chlorine gas is generally present in the manufacture of chlorinated lime, glazed bricks, and in bleaching operations, and is very apt to produce, when present in the proportion of 1-5 parts in 100,000 of air, a cachectic condition, asthma, bronchitis, caries of the teeth, and acne or pimples upon the face, while in a more concentrated form-40-60 parts in 100,000—-it produces a violent cough and extreme difficulty in breathing.

Hirt describes these attacks as follows: "In spite of the aid of the auxiliary respiratory muscles the entrance of the air to the lungs is insufficient, and the staring eyes, the livid lips, and the cold, clammy perspiration plainly show the mortal agony of the patient. The pulse is small and temperature decreased. These phenomena disappear upon removal to the fresh air, and a few hours later the workman is found enveloped in chlorine and hydrochloric acid vapors in his accustomed place in the factory. The attacks seem to be but rarely fatal, unless the volume exceeds 60 parts per 100,000."

BLEACHING ESTABLISHMENTS.

The Massachusetts Board of Health, in its summary of five bleacheries, with about 1,200 employees, speaks approvingly of the general arrangements for ventilation and says: "The odors of bleaching powders, although observable in each of the rooms where that substance is employed, were in no case so strong as to be disagreeable or to cause discomfort. In one of the establishments the persons exposed to the lint dust which escapes during unbaling and stitching together of the cotton cloth all looked pale and sickly."

IODINE AND BROMINE VAPORS.

Iodine and bromine vapors may produce toxic symptoms. The fumes of iodine are liable to cause catarrhal conditions of the nose, eyes, and air passages, and frequent headaches, while chronic iodine. poisoning produces a cachectic condition, wasting of the testicles, and loss of sexual power. Persons engaged in the manufacture of bromine

are said to suffer quite frequently with a form of bronchial asthma, dizziness, and general weakness, while concentrated vapors have been known to produce spasm of the glottis and suffocation.

Bromine preparations are used to a considerable extent in photography. Schuler' describes three cases, one of which proved fatal, in men who prepared "brommetyl" from wood alcohol and sulphuric acid. In all of these three cases there were pronounced symptoms of nausea, spasms, and trembling of the extremities and diminished bodily temperature.

TURPENTINE.

Turpentine vapors in excess may produce gastric and pulmonary catarrh, slow and painful micturition and bloody urine, headache, roaring in the ears, and other nervous symptoms. Schuler observed among the workers in calico printing marked emaciation, loss of appetite, rapid pulse, and more or less headache, which he attributed to the turpentine vapors. In small doses no unpleasant symptons are observed. The odor of violets in the urine is one of its remarkable effects. The use of impure turpentine for cleaning purposes has been known to produce obstinate eczema of the hand.

PETROLEUM.

Concentrated vapors of coal oil are said to produce loss of sensation, and the workmen in refineries occasionally show symptoms like those observed in drunken persons, fall into a profound sleep, or suffer from loss of memory, dizziness, headache, and chronic bronchial catarrhs. Pustular, furuncular, and eczematous affections of the hands are also quite common in persons handling this and paraffin oil. The latter is also true of persons handling creosote and tar, unless protected by impermeable gloves. The dangers from explosions in the petroleum industry must also be guarded against.

BENZINE VAPORS.

Dr. Neisser, in 1907, reports an instance where three laborers in a carpet-cleaning establishment in which large quantities of benzine had been used were found unconscious upon the floor and had to be restored by oxygen inhalation. The toxic symptoms are similar to those produced by concentrated petroleum vapors, and the danger from explosions and fire are of course even greater.

Deutsche Viertelj. f. off. Gesundheitpflege, Bd. 31, p. 696.

CARBON MONOXIDE.

Carbon monoxide, or coal gas, when present in sufficient amount paralyzes, so to speak, the red corpuscles by depriving them of their oxygen and combining with the hæmoglobin, which results in deficiency of oxygen in the blood and serious toxic symptoms, which may end in death by producing a rapid parenchymatous degeneration of the liver, spleen, and heart. This gas is often present in gas and smelting works and around coke or charcoal furnaces, and 4 per cent by volume in the air will produce toxic symptoms, and more than I per cent is rapidly fatal to animal life. The workmen sometimes, though not as often as is supposed, suffer from the chronic form of poisoning, such as headache, dizziness, slow pulse, anæmia, general debility, and diseases of the respiratory and digestive organs. The acute symptoms of coal-gas poisoning are increased respiration and pulse, violent headache, dizziness, and roaring in the ears. These are soon followed by symptoms of depression, nausea and vomiting, numbness, drowsiness, muscular relaxation, paralysis, sighing respiration, slowness of the pulse and feeble heart action, dilatation of the pupils, diminished bodily temperature, and, if continued, convulsions, stertorous breathing, and death by suffocation. If death does not occur the patient is apt to suffer for some time from headache, physical and mental depression, paralysis of speech and of the sphincters, convulsive twitching, and general muscular weakness, while pleurisy and pneumonia are also frequent.

CARBONIC-ACID GAS.

The chronic effect of carbonic-acid gas has already been alluded to. Well sinkers and miners are occasionally suffocated owing to the presence of a large volume of this gas evolved from the soil and which has collected in deep shafts. It is one of the constituents of the "choke damp" in the mines and also present in cellars. It is also a product of fermentative processes, and the anæmic and debilitated conditions of miners, vintners, distillers, brewers, and yeast makers is believed to be partly due to an excess of carbonic acid, which diminishes the amount of oxygen in the air. The acute symptoms are loss of consciousness and locomotion, generally preceded by difficulty in breathing, headache, depression, drowsiness or mental excitement, sometimes convulsions. Prompt removal of the patient into fresh air will lead to rapid recovery.

CARBON DISULPHIDE.

Carbon disulphide is used in certain processes in the manufacture of vulcanized india rubber, and also in the extraction of fats, and may