On the colouring matter of the pink and red vulcanite used in dentistry : with remarks on the occasional occurrence of symptoms of poisoning, probably dependent upon the vermilion used as a pigment / by W. Bathurst Woodman.

  • Woodman, W. Bathurst (William Bathurst), 1836-1877.
Date:
[1875?]
Catalogue details

Licence: Public Domain Mark

Credit: On the colouring matter of the pink and red vulcanite used in dentistry : with remarks on the occasional occurrence of symptoms of poisoning, probably dependent upon the vermilion used as a pigment / by W. Bathurst Woodman. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    tinted ones usually contained about one-third, or some 33 to 34 per cent, of this pigment,—a result which differs but little from that given in Appendix V. from the Dental Cosmos, which states the percentage at 36 per cent. The proportion of pigment can only be approximatively judged by the colour, some very pretty and natural-looking specimens containing less vermilion than some which do not look so well. Although certain natural resemblances in ap- pearance and composition led me to believe that nearly all the rubbers used in this country were manufactured by some three or four, or at most, half a dozen firms, yet 1 must own I was surprised to find this mineral pigment in all the specimens examined (the total number of samples being nearly a hundred).* Mr. Turner, however, has given what appears to me a very reasonable explanation, which I suppose to be the vera causa, namely, that there is scarcely any other colouring matter known, at least of the desired tint, which would withstand the action of the H2S, or hy- drogen sulphide, and other sulphur compounds (such as SO2) generated in the process of hardening or vulcanizing the rubber. I think I * It is an act of only simple justice to Messrs. Ash to state, that the rubbers manufactured by theui were the best and most evenly mixed with the pigment of uU the samples ex- amined.