"Not poppy, nor mandragora, Nor all the drowsy syrups of the world Shall ever medicine thee to that sweet sleep Which thon own'dat yesterday."

Therefore, he who would sleep well should join in the prayer of Dr. Johnson, for

"Obedient passions and a will resigned."

Add to these the calming influence of a conscience void of offence towards God, and towards man, and we are in possession of the best mental preparation for gentle slumber. " When Ptolemy, king of Egypt," says an old writer, " had posed the seventy interpreters in order, and asked the nineteenth man what would make one sleep quietly in the night, he told him the best way was to have divine and celestial meditations, and to use honest actions in the day-time." Our last question is, What is the final cause of sleep ? Why should the senses and voluntary motions be suspended ? Why have they not been allowed to continue uninterrupted, like the pulsations of the heart, and the action of other organs? But, after all, no organs of the body are really sleepless. The heart, in the midst of its seemingly continuous pulsations, has its halt. The lungs rest at the end of every expiration. The stomach is not, or ought not to be, always at work. The great difference is, that while the organs of the vegetable life take their repose in snatches, frequently returning, those of relative life have long spells of sleep, and then uninterrupted work. But without dwelling on this view, it would be easy to shew that were sleep abolished, the whole economy of the body would require to be altered. Were the nervous organs of sensation and voluntary motion to continue in unslackened exercise, they must have a corresponding supply of blood; but as that which must then be expended upon them could not be applied to the wants of other organs, as is now the case in sleep, a greater quantity of blood must be formed. This requirement must entail a change in the dimensions and qualities of the blood vessels, in the propulsive powers of the heart, and a change in the apparatus of respiration. But the formation of the increased quantity must engender the need of increased digestion and assimilation; and the organs devoted to these functions would require an increase in their extent and endowments, not only for their greater amount of function, but also because they would no longer perform them under the present favourable circumstances, incident to the state of repose. Many other illustrations might be given of the disturbance which must occur in the whole of the present system. Supposing, however, that such a change were effected, and the animal organization moulded on an entirely new plan, how would it stand in relation to the circumstances in which it exists? More food would be required; and, in many cases, this is by no means more than adequate to the present need both of man and animals. More air must be consumed. And it is questionable whether, to the supposed sleepless organisms, the present density of the atmosphere and proportion of oxygen would be adequate. Whether such consumers, and, I might add, vitiators of air could be as gregarious and social, might be doubted. But without dwelling upon any other arrangement of external nature than that of darkness, this surely would be enough to shew the harmony subsisting between the sleep of animals, and the media of their existence. For the exceptions in the case of predatory mammalia, or of animals which in their burrows and caverns have, even in the day-time, a night spread around them, are trifling in comparison with the hordes that toil and bask and sport in the sunshine. How would the hours of night pass to animals capable of sense and motion, yet debarred from the exercise of them, and having no such resources as belong to reflective man under similar circumstances? But not to press the argument further, we might ask what would be gained by this ever-vigilant state? It may be answered, - more time for man to work in, to do his mighty deeds, to realize his visions of glory, and his schemes of benevolence. For the lower animals, - more time to feel the pleasures of their limited existence, and to enjoy the exercise of such faculties as they possess. But, is the feeling of existence in these beings always one of pleasure ? Are their powers always exerted with delight? Would it be a gain to the timid deer, that their fleetness should unceasingly be called into action to elude the chase of the sleepless wolf? Would it add to the happiness of the gentle dove, to expect the downward swoop of the hawk in the night as well as day ? And are man's thoughts so free from evil, that they could be trusted to engender actions all the livelong hours ? Surely it is better that the hand of the violent man should be stayed by sleep's soft compulsion. Better that the busy, plotting brain, devising mischief, should be caught and entangled in its own dreamy meshes. Better that the lips of the tyrant should be sealed for a few hours, for mercy instead of doom may drop from them after the night's calm and refreshment. Better that the world should have a respite, if not a reprieve, from the horrors that await the waking of armed men. It is something gained if only a few hours are saved before the sky is red with the light of flaming cities, and the air afflicted with groans and wailings, and curses and war-cries.

But we need not contemplate sleep as the mere interruption of deeds of crime, and scenes of violence. Its associations have more of gentleness than of terror. To sleep is to pause from the hurrying whirl of life; to rest after all its toil, and struggles, and agitation; to see no sights of pain and grief, and "all the ill things that are done i'the sun;" to hear no sighs, "no stifled sobs, no loud lament; " to forget all cares, and losses, and heartaches. It is, in fact, to fall into a state which seems to comprehend within it, all that is most gentle and soothing in idea, - an epitome of pathos, - an ever-recurring text of mercy and type of tenderness, - an armistice between the contending powers of good and evil, - a relaxation of the "dread strife Of poor humanity's afflicted will,' Straggling in Tain with ruthless destiny."