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do ſo, as no patent could ſtand on ſuch a ſpecification. For, ſaid his Lordſhip, I think more depends in the compoſition of a medicine, on the proportion of the drugs, than on their quality; as we find it a fact too notorious, that what even preſerves life, taken in too great quantity, will in ſome caſes inſtantly deſtroy it. Mercury for inſtance, though uſed with a more general good effect, perhaps, than any other article in the materia medica, would produce the moſt baleful conſequences, applied without regard to proportion.
This, my Lord, was the opinion of the illuſtrious Earl Mansfield.—I will now proceed to ſtate what I heard from the mouth of the equally excellent Lord Kenyon, who now occupies the ſame judgment ſeat, with ſuch diſtinguiſhed honour and propriety. The circumſtance to which I allude is a remark his Lordſhip made when trying the cauſe of Turner verſus a chymiſt, for infringement on his patent, for making a yellow colour by a calcination of lead. In the courſe of this trial, which was of conſiderable length, and on which I attended the whole time, I heard his Lordſhip give his opinion on what the law required in a Specification. It was in effect as fol-
lows,
