Our ancestors had recourse to various devices to procure sound sleep. Borde recommends a good draught of strong drink before going to bed; Burton, a nutmeg and ale, with a good potation of muscadine with a toast; while Aetius recommends a sup of vinegar, which, according to Piso, "_attenuat melancholiam et ad conciliandum somnum juvat_." Oppression from repletion will occasion fearful dreams and the night-mare; and bodily sufferings, when exhaustion has brought on sleep, will also be attended with alarming and painful visions. Levinus Lemnius recommended to sleep with the mouth shut, to promote a regular digestion by the exclusion of too much external air. The night-mare is admirably described in Dryden's translation of Virgil: And as, when heavy sleep has closed the sight, The sickly fancy labours in the night, We seem to run, and, destitute of force, Our sinking limbs forsake us in the course: In vain we heave for breath; in vain we cry; The nerves, unbraced, their usual strength deny, And on the tongue the falt'ring accents die. In the Runic theology it was regarded as a spectre of the night, which seized men in their sleep, and suddenly deprived them of speech and of motion. It was vulgarly called witch-riding, and considered as arising from the weight of fuliginous spirits incumbent on the breast. _Somnus ut sit levis, sit tibi coena brevis_, is the ancient axiom of our distich, That your sleep may be light, Let your supper be slight. Notwithstanding this rule of health, it is nevertheless true that many persons sleep more soundly after a hearty supper; and, most unquestionably, dreams are more frequent towards morning than in the beginning of the night. In my opinion, I should apprehend that the sound sleep of supper-eaters is to be attributed to the narcotic nature of their potations, more than the meal, although the _siesta_ of southern countries might be advanced in favour of a contrary opinion. When philosophers speak of dreams being mental operations independent of the will, they speak vaguely, for the operations of the mind when we are awake are too frequently uncontrolled by volition. Did we possess this power over our rebellious thoughts, who would constantly ponder on a painful subject? Our thoughts cannot be suspended at will, and their influence has been beautifully described by Shakspeare: My brain I'll prove the female to my soul, My soul the father; and these two beget A generation of still breeding thoughts.