[80] I have seen a pretty singular Consequence from the Abuse of mercurial Unction for the Itch; whether it happened from the Strength or Quantity of the Ointment, or from taking Cold after applying it, as this Subject, a healthy Youth of about sixteen, probably did, by riding three or four Miles through the Rain. But without any other previous Complaint, he awoke quite blind one Morning, wondering, as he said, when it would be Day. His Eyes were very clear, and free from Inflammation, but the Pupil was wholly immoveable, as in a _Gutta serena_. I effected the Cure by some moderate Purges repeated a few Times; by disposing him to sweat by lying pretty much in Bed (it being towards Winter) and by promoting his Perspiration, chiefly with Sulphur: after which the shaved Scalp was embrocated with a warm nervous Mixture, in which Balsam of _Peru_ was a considerable Ingredient. In something less than three Weeks he could discern a glowing Fire, or the bright Flame of a Candle. As his Sight increased, he discerned other Objects, which appeared for some Days inverted to him, with their Colours confused; but Red was most distinguishable. He discovered the Aces sooner than other Cards; and in about six or seven Weeks recovered his full Sight in all its natural Strength, which he now enjoys. _K._ Sec. 347. If this Disorder becomes very inveterate and tedious, it exhausts the Patient, in Consequence of its not suffering him to sleep at Nights, as well as by his restless Irritation; and sometimes even brings on a Fever, so that he falls away in Flesh, and his Strength abates. In such a Case he must take, 1, a gentle Purge. 2, Make Use frequently of warm Baths. 3, He must be put on the Regimen of Persons in a State of Recovery. 4, He must take Morning and Evening, fifteen Days successively, the Powder No. 53, with the Ptisan No. 26. This Malady is often very obstinate, and then the Medicines must be varied according to the Circumstances, the Detail of which I avoid here. Sec. 348. After giving repeated Purges in such obstinate Cases, mineral Waters abounding with Sulphur, such as [81] those of _Yverdun_, &c. often effect a Cure; and simple cold Bathings in Rivers or Lakes have sometimes succeeded in very inveterate Cases of this Disorder. [81] Sea water, and those of _Dulwich_, _Harrigate_, _Shadwell_, &c. will be full as effectual. _K._ Nothing conduces more to the long Continuance of this Malady, than the Abuse of hot Waters, such as infusions of Tea, &c.