The frequency of such poisonings caused Schaefer,[4] Inspector of Factories in Hamburg, to go fully into the question. He lays stress on the dangerous nature of paints containing a high proportion of benzol, but considers use of unpurified constituents with boiling-point between 130°-170° C., such as solvent naphtha, as free from risk (cf. in Part II the experiments on benzene and the commercial kinds of benzol). Schaefer mentions that in 1903 and 1904 cases of unconsciousness from painting the inside of boilers were numerous. The proportion of benzol in the paints was 20-30 per cent. In 1905 and 1906 the cases were attributable rather to inhalation of hydrocarbons in cleaning of apparatus. Use of ‘Dermatin’ affected two painters. One case in 1906 happened to a man painting the double bottom of a ship in Hamburg harbour with ‘Black Varnish Oil’ through the manhole, in doing which he inhaled much of the fumes. This paint consisted of coal-tar pitch in light coal-tar oil, the latter constituent (distilling at 170° C.) amounting to 31-33 per cent. Investigation showed further that the bulk of the tar oil volatilised at ordinary temperatures and so quickly dried. Sulphuretted hydrogen gas was given off on slight warming. The person after using it for some time felt poorly, and then became ill with severe inflammation of the respiratory passages, which proved fatal after twenty-four days. Several similar cases occurred in 1908 and 1909. Painting the inside of a boiler with ‘Auxulin’ caused unconsciousness in four persons, of whom three were rescuers. A fatal case was due to use of a patent colour containing 30-40 per cent. benzol in an entirely closed-in space (chain-well), although the worker was allowed out into fresh air at frequent intervals. A case of chronic industrial xylene poisoning is described in a worker using it for impregnating indiarubber goods. The symptoms were nervous, resembling neurasthenia. Some of the cases of poisoning, especially when severe and fatal, in the production of distillation constituents of coal tar are doubtless attributable to _sulphuretted hydrogen gas_. Thus in England, in the years 1901-3, there were eleven fatal and as many other severe cases reported from tar distilleries, of which the majority were due to sulphuretted hydrogen gas. One case of _carbonic oxide_ poisoning in coal-tar distillation is described.[5] In cleaning out pitch from a still fourteen days after the last distillation a workman succumbed to carbonic oxide poisoning. This is at all events a rare eventuality, since no other case is to be found in the literature of the subject, but it is a proof that in the last stage of coal-tar distillation carbonic oxide plays a part. Mention must be made of the frequent occurrence of severe skin affections in _anthracene workers_; they take the form of an eruption on the hands, arms, feet, knees, &c., and sometimes develop into cancer.