Fat and oil are extracted from seeds, bones, &c., by carbon bisulphide, benzine, or ether, and, to avoid evaporation, the vessels are as airtight as possible and arranged, as a rule, for continuous working. _Vulcanisation_ is the rendering of rubber permanently elastic by its combination with sulphur. It is effected by means of chloride of sulphur, sulphide of barium, calcium, or antimony, and other sulphur-containing compounds, heat and pressure, or by a cold method consisting in the dipping of the formed objects in a mixture of carbon bisulphide and chloride of sulphur. The process of manufacture is briefly as follows: The raw material is first softened and washed by hot water and kneading in rolls. The washed and dried rubber is then mixed on callender rolls with various ingredients, such as zinc white, chalk, white lead, litharge, cinnabar, graphite, rubber substitutes (prepared by boiling vegetable oils, to which sulphur has been added, with chloride of sulphur). In vulcanising by aid of heat the necessary sulphur or sulphur compound is added. Vulcanisation with sulphur alone is only possible with aid of steam and mechanical pressure in various kinds of apparatus according to the nature of the article produced. In the cold vulcanisation process the previously shaped articles are dipped for a few seconds or minutes in the mixture of carbon bisulphide and chloride of sulphur and subsequently dried in warm air as quickly as possible. In view of the poisonous nature of carbon bisulphide, benzine is much used now. In the cold method use of chloride of sulphur in benzine can replace it altogether. Instead of benzine other solvents are available—chlorine substitution products of methane (dichlormethane, carbon tetrachloride). In other processes _rubber solvents_ are largely used, for instance, acetone, oil of turpentine, petroleum benzine, ether, and benzene. Rubber solutions are used for waterproofing cloth and other materials. Similar to the preparation and use of rubber is that of guttapercha. But vulcanisation is easier by the lead and zinc thiosulphate process than by the methods used in the case of rubber. EFFECTS ON HEALTH OF CS₂ AND OTHER DANGERS TO HEALTH IN THE RUBBER INDUSTRY.—In the manufacture of carbon bisulphide little or no danger is run either to health or from fire. In the rubber trade the poisonous nature of _benzine_ and _chloride of sulphur_ have to be borne in mind, and also the considerable risk of _lead poisoning_ in mixing. Cases of plumbism, especially in earlier years, are referred to.[1] _Benzine_ poisoning plays only a secondary part in the rubber industry. No severe cases are recorded, only slight cases following an inhalation of fumes.