It is needless to observe that Van Helmont was mistaken, in supposing that this _offa_ was the matter of calculus. Spirit of urine was a strong solution of carbonate of ammonia. The alcohol precipitated this salt; so that his _offa_ was merely _carbonate of ammonia_. Nor is there the shadow of evidence that alcohol, as Van Helmont thought it did, ever makes its way into the mass of humours; yet his notion of the origin of calculi is not less accurate, though of course he was ignorant of the chemical nature of the various substances which constitute these calculi. From this reasoning Van Helmont was induced to reject the term _tartar_, employed by Paracelsus. To avoid all false interpretations he substitutes the word _duelech_, to denote the state in which the spirit of urine precipitates and gives origin to these calculous concretions. As all diseases proceeded in his opinion from the archeus, the object of his treatment was to calm the archeus, to stimulate it, and to regulate its movements. To accomplish these objects he relied upon dietetics, and upon acting on the imaginations of his patients. He considered _certain words_ as very efficacious in curing the diseases of the archeus. He admitted the existence of the universal medicine, to which he gave the names of _liquor alkahest_, _ens primum salium_, _primus metallus_. Mercurials, antimonials, opium, and wine, are particularly agreeable to the archeus, when in a state of delirium from fever. Among the mercurial preparations, he praises what he calls _mercurius diaphoreticus_ as the best. He gives no account of the mode of preparing it; but from some circumstances I think it must have been _calomel_. He considers it as a sovereign remedy in fevers, dropsies, diseases of the liver, and ulcers of the lungs. He employed the red oxide of mercury as an external application to ulcers. The principal antimonial preparations which he employed were the hydrosulphuret, or _golden sulphur_, and the deutoxide, or _antimonium diaphoreticum_. This last medicine was used in scruple doses--a proof of its great inertness compared with the protoxide of antimony. Opium he considered as a fortifying and calming medicine. It contains an acrid salt and a bitter oil, which give it the virtue of putting a stop to the errors of the archeus, when it was sending its acid ferment into other acid parts of the body. Van Helmont assures us that he wrought many important cures by the employment of wine.