One end of a bent tube was fixed in a phial full of lime-water; the other end in a bottle of the tincture of myrrh. The junctures were carefully luted, and the phial containing the tincture of myrrh was placed in water, heated almost to the boiling point, by the lamp of a tea-kettle. A number of air-bubbles were separated, but probably not of the mephitic kind, for no precipitation ensued in the lime water. This experiment was repeated with the _tinct. tolutanae, ph. ed._ and with _sp, vinos. camp._ and the result was entirely the same. The medicinal action therefore of the vapours raised from such tinctures, cannot be ascribed to the extrication of fixed air; of which it is probable bodies are deprived by _chemical solution_ as well as by _mixture_. If mephitic air be thus capable of correcting purulent matter in the lungs, we may reasonably infer it will be equally useful when applied externally to foul ULCERS. And experience confirms the conclusion. Even the sanies of a CANCER, when the carrot poultice failed, has been sweetened by it, the pain mitigated, and a better digestion produced. The cases I refer to are now in the Manchester infirmary, under the direction of my friend Mr. White, whose skill as a surgeon, and abilities as a writer are well known to the public. Two months have elapsed since these observations were written,[16] and the same remedy, during that period, has been assiduously applied, but without any further success. The progress of the cancers seems to be checked by the fixed air; but it is to be feared that a cure will not be effected. A palliative remedy, however, in a disease so desperate and loathsome, may be considered as a very valuable acquisition. Perhaps NITROUS AIR might be still more efficacious. This species of factitious air is obtained from all the metals except zinc, by means of the nitrous acid; and Dr. Priestley informs me, that as a sweetener and antiseptic it far surpasses fixed air. He put two mice into a quantity of it, one just killed, the other offensively putrid. After twenty-five days they were both perfectly sweet. In the ULCEROUS SORE THROAT much advantage has been experienced from the vapours of effervescing mixtures drawn into the _fauces_[17]. But this remedy should not supersede the use of other antiseptic applications.[18]