Other marvelous effects than routing the devil, which Hildegard attributes to gems in the course of the fourth book of the _Subtilitates_, are to confer intellect and science for the day, to banish anger and dulness, bestow an equable temper, restrain lust, cure all sorts of diseases and infirmities, endow with the gift of sound speech, prevent thefts at night, and enable one to fast. These marvelous results are produced either by merely having the stone in one’s possession, or by holding it in the hand, placing it next the skin, taking it to bed with one and warming it by the heat of the body, breathing on it, holding it in the mouth especially when fasting, suspending it about the neck, or making the sign of the cross with it. In the cure of insanity by use of the magnet the stone should be moistened with the patient’s saliva and drawn across his forehead while an incantation is repeated.[400] A man may be brought out of an epileptic fit by putting an emerald in his mouth.[401] Having recovered, he should remove the gem from his mouth and say, “As the spirit of the Lord filled the earth, so may His grace fill the temple of my body that it may never be moved.” This ceremony is to be repeated on nine successive mornings, and that here the gem is as important as the prayer is indicated by the direction that the patient should have the gem with him each time and take it out and look at it as he repeats the incantation. Different is the procedure for curing epilepsy by means of the gem _achates_.[402] In this case the stone should be soaked in water for three days at the full moon; this water should be slightly warmed, and then preserved, and all the patient’s food cooked in it _dum luna tota crescat_. The gem should also be placed in everything that he drinks. This astrological procedure is to be repeated for ten months. [Sidenote: Remarkable properties of fish.] We have already heard that certain fish have the property of expelling demons. Fish also have other remarkable virtues. The eye of a _copprea_, worn in a gold or silver ring so that it touches one’s finger, arouses a sluggish intellect.[403] The lung of a tunny fish, taken in water, is good for a fever, and it keeps one in good health to wear shoes and a belt made of its skin.[404] Pulverized salmon bones are recommended for bad teeth.[405] But eating the head of a _barbo_ gives one a headache and fever.[406] Hildegard also tells some wonderful stories concerning the modes of generation of different varieties of fish. In the _Causae et curae_[407] for dimness of the eyes it is recommended to dry some walrus skin in the sun, soften it in pure wine, and apply it in a cloth between the eyes at night. It should be removed at midnight and applied only on alternate nights for a week. “Either it will remove dimness of the eyes, or God does not permit this to be done.” [Sidenote: Use of the parts of birds.]