This Proposition being made, M. _Boyle_ soon gave order for an _Apparatus_, to put it to Experiment; wherein at several times, upon several Doggs, _Opium_ & the Infusion of _Crocus Metallorum_ were injected into that part of the hind-legs of those Animals, whence the larger Vessels, that carry the Blood, are most easy to be taken hold of: whereof the success was, that the _Opium_, being soon circulated into the Brain, did within a short time stupify, though not kill the Dog; but a large Dose of the _Crocus Metallorum_, made another Dog vomit up Life and all: All which is more amply and circumstantially delivered by Mr. _Boyle_ in his Excellent Book of the _Usefulness of Experimental Philosophy_, Part 2. Essay 2. pag. 53. 54. 55. Where 'tis also mention'd, that the fame of this Invention and of the succeeding Tryals being spread, and particularly coming to the knowledge of a foreign _Ambassadour_, that was Curious, and then resided in _London_, it was by him tryed with some _Crocus Metallorum_, upon a Malefactor, that was an inferiour Servant of his; with this success, that the Fellow, as soon as ever the Injection began to be made, did, either really or craftily, fall into a swoon; whereby, being unwilling to prosecute so hazardous an Experiment, they desisted, without seeing any other effect of it, save that it was told the Ambassadour, that it wrought once downwards with him: Since which time, it hath been frequently practised both in _Oxford_ & _London_; as well before the _Royal Society_, as elsewhere. And particularly that Learned {130} Physitian, Dr. _Timothy Clerk_, hath made it part of his business, to pursue those Experiments with much industry, great accurateness, and considerable observations thereon; which above two years since, were by him produced and read before the _Royal Society_, who thereupon desired him, as one of their Members, to compleat, what he had proposed to himself upon that subject, and then to publish the same: the Effect whereof 'tis hoped, will now shortly appear, and not prove unwelcome to the Curious.