Paracelsus and Van Helmont, expressly declare, that there is a certain fluid in nature, capable of reducing all sublunary bodies, as well hemogeneous as mixed, into their _ens primum_, or original matter of which they are composed; or into an uniform equable and potable liquor, that will unite with water, and the juices of our bodies, yet will retain its radical virtues; and if mixed with itself again, will thereby be converted into pure elementary water. This declaration, seconded by the asseveration of Van Helmont, who solemnly declared himself possessed of the secret, excited succeeding Chemists and Alchymists to the pursuit of so noble a menstruum. Mr. Boyle was so much attracted with it, that he frankly acknowledged he had rather been master of it, than of the Philosopher’s Stone. In short, it is not difficult to conceive, that bodies might originally arise from some first matter, which was once in a fluid form. Thus, the primitive matter of gold is, perhaps, nothing more than a ponderous fluid, which, from its own nature, or a strong cohesion or attraction between its particles, acquires afterwards a solid form. And hence there does not appear any absurdity in the notion of an universal ens, that resolves all bodies into their Ens Genitate. The Alcahest is a subject that has been embraced by many anthers; _e. g._ Pantatem, Philalettes, Tachenius, Ludovicus, &c. Boerhaave says, a library of them might be collected; and Werdenfelt, in his treatise de Secretis Adeptorum, has given all the opinions that have been entertained concerning it. The term Alcahest is not peculiarly found in any language: Helmont declares, he first observed it in Paracelsus, as a word that was unknown before the time of that author, who in his second book, _De Viribus Membrorum_, treating of the liver, has these rather remarkable words: _Est etiam_ alkahest _liquor_, magnam sepates conservandi et confortandi, &c. “There is also the liquor _Alkerhest_, of great efficacy in preserving the liver; as also in curing hydropsical and all other diseases arising from disorders of that part. If it have once conquered its like, it becomes superior to all other hepatic medicines; and though the liver itself was broken and dissolved, this medicine should supply its place.” It was this passage alone, quoted from Paracelsus, that stimulated succeeding chemists to an enquiry after the Alkahest; there being only another indirect expression, in all his work, relating to it.