(2) =Carbonic Oxide= in the proportion of more than 1 per cent. is rapidly fatal, and has poisoned when under 1∕2 per cent. Poisoning by its means occurs where charcoal stoves are used, and especially when the charcoal is burnt in rooms with no chimney flue. This is an occasional mode of suicide on the continent. Carbonic oxide is a much more deadly poison than the dioxide (carbonic acid); it forms a stable compound with the hæmoglobin of the red blood-corpuscles, displacing oxygen from them, and is got rid of with great difficulty. Lace-frame makers place a coke stove under their work, and thus inhale the invisible gas. Headache, giddiness, irregular action of the heart, and depression of the general health result. Carbonic oxide is the most poisonous constituent of coal-gas, and is present in much larger quantity in carburetted water-gas with which coal-gas is now commonly mixed, than in pure coal-gas (page 115). (3) The inhalation of =Sulphuretted Hydrogen= produces headache, nausea, and diarrhœa; but in manufactures involving the inhalation of a small proportion of this gas the symptoms are much slighter. (4) =Sulphurous Acid= is always present in small quantities in the air of towns, derived from the combustion of coal and coal-gas. Straw-bleachers and the bleachers in cotton and worsted manufactories, often suffer from severe cough and bronchitis due to inhaling its irritating vapours. (5) =Carbon Disulphide= when vaporised and inhaled produces headache, general muscular pains, and nervous depression. It is used in the manufacture of waterproof coats, toy balloons, etc. (6) =Ammonia= produces irritation of the eyes and bronchial irritation. Hat-makers commonly suffer from its effects, being generally pale and feeble. It is difficult to say how much is due to the ammonia, and how much to the high temperature at which they work. (7) =Acid Fumes= are very irritating to the lungs, and in the case of alkali manufactures, they destroy all vegetation for considerable distances. _Hydrochloric acid_ produces great irritation, and chlorine even more so. The fur-dyer is not only subject to the dangers of dust, but also of the fumes of _nitric acid_, used to remove fat and give certain shades of colour to the fur. (8) =Other Vapours= evolved in various processes produce special symptoms. House-painters suffer from the inhalation of _turpentine vapour_, headache and loss of appetite commonly resulting. The symptoms from the commonly coexistent lead-poisoning are distinct. Brush-makers have a persistent cough, due to the inhalation of _resinous fumes_, evolved in making brushes. _Workers in paraffin_ are liable to an irritative disease of the hair-follicles of the body, followed by the formation of scars, almost like small-pox marks.