But, as far as we know, there is an entire want of any evidence that will satisfactorily show that the inconvenience suffered by wearers of these dyed goods has been owing to the dyeing material. Years must elapse before chemists or physicians can hope to become thoroughly informed of the physiological action produced by the cutaneous absorption of the thousands of new products which the ingenuity and industry of technological chemists have made available for the manufacture of colors; they are also new to science, most of them very complex in their constitution, and so dissimilar to previously studied compounds used by the dyer, that it may be said we have nearly everything to learn concerning their action upon the human economy. With respect to dyed woolen and silk goods it is almost entirely a question as to the innocence or otherwise of the coloring matter itself, which in nine cases out of ten is an organic body containing no mineral matter of any sort, and not requiring the assistance of any mordant to enable it to dye. Considerations of arsenic, or antimony, or mercury existing in the dyed stuffs are absolutely excluded. In a few cases the dyestuff is a zinc compound, and zinc in small traces may possibly be fixed by the material, but this metal is not known to be actively noxious. Textiles made from fibers of animal origin do not require, and as a rule do not tolerate, the addition of any metal in dyeing with the artificial colors, and if the manufacture of the color require the use of a metal, such as arsenic, which by unskillfulness or carelessness is left in it when delivered to the dyer, the tendency of the animal fiber is to reject it.