_Turpentine oil._.—Turpentine oil is a peculiar-smelling, colourless liquid of the composition C₁₀H₁₆; different reactions show that turpentine oil contains the aromatic nucleus (cymene). It is used in the manufacture of varnish, and thus can cause industrial poisoning by inhalation of fumes. Even from 3 to 4 mg. of vapour of turpentine oil per litre of air brings on severe symptoms. Turpentine oil acts as a local irritant, and when absorbed into the system has an exciting effect upon the central nervous system. Inhalation of large quantities of turpentine vapour cause rapid breathing, palpitation, giddiness, stupor, convulsions, and other nervous disturbances, pains in the chest, bronchitis, and inflammation of the kidneys. The last-mentioned symptom also arises from the chronic action of turpentine vapours. _Pyridine._—Pyridine (C₅H₅N), a colourless liquid of peculiar odour, is employed as well as methylalcohol in denaturing alcohol. The disturbance of health observed in workers occupied with the denatured spirit are probably mainly due to the inhalation of fumes of methylalcohol. Pyridine is comparatively innocuous. Eczema, from which persons suffer who come into contact with denatured spirit, is ascribed to the action of pyridine. Larger doses produce a paralysing effect, but this need not be considered in its industrial use. _Nicotine, tobacco._—According to various published statements, effects among tobacco factory workers are attributed to the nicotine contained in tobacco dust and to the aroma which fills the air. Nicotine in large doses has at first an exciting followed by a paralysing effect upon the central nervous system; it causes moreover contraction of the unstriped muscles and has a local irritant effect. The symptoms of illness ascribed to nicotine are: conjunctivitis, catarrh of the air passages, palpitation, headache, want of appetite, and, particularly, tendency to abortion and excessive menstruation. Severe industrial poisoning due to nicotine has only been observed in workers who chewed tobacco leaves. _Poisonous wood._—The symptoms of disease noticed in workers who manipulate certain kinds of wood are attributed by some writers to the presence of alkaloids. Such knowledge as we have of the illness due to them—they are evidently of the nature of poisoning—is referred to at the end of Part I. PART III _PREVENTIVE MEASURES AGAINST INDUSTRIAL POISONING_ I _GENERAL MEASURES_ In discussing preventive measures against industrial poisoning the deductive method from the general to the particular will be followed. The numerous instances of poisoning mentioned in Part I afford a practical basis on which to formulate general rules before passing on to describe special measures. Technical details will be omitted, as they must be left to the technical expert whose business it is to draw up the plans as a whole and to modify them according to the requirements of individual cases.