This disposition to repose in the early weeks of the infant's life must not be interfered with; but this period having expired, great care is necessary to induce regularity in its hours of sleep, otherwise too much will be taken in the day-time, and restless and disturbed nights will follow. The child should be brought into the habit of sleeping in the middle of the day, before its dinner, and for about two hours, more or less. If put to rest at a later period of the day, it will invariably cause a bad night. At first the infant should sleep with its parent. The low temperature of its body, and its small power of generating heat, render this necessary. If it should happen, however, that the child has disturbed and restless nights, it must immediately be removed to the bed and care of another female, to be brought to its mother at an early hour in the morning, for the purpose of being nursed. This is necessary for the preservation of the mother's health, which through sleepless nights would of course be soon deranged, and the infant would also suffer from the influence which such deranged health would have upon the milk. When a month or six weeks has elapsed, the child, if healthy, may sleep alone in a cradle or cot, care being taken that it has a sufficiency of clothing, that the room in which it is placed is sufficiently warm, viz. 60 degrees, and the position of the cot itself is not such as to be exposed to currents of cold air. It is essentially necessary to attend to these points, since the faculty of producing heat, and consequently the power of maintaining the temperature, is less during sleep than at any other time, and therefore exposure to cold is especially injurious. It is but too frequently the case that inflammation of some internal organ will occur under such circumstances, without the true source of the disease ever being suspected. Here, however, a frequent error must be guarded against,-- that of covering up the infant in its cot with too much clothing throwing over its face the muslin handkerchief--and, last of all, drawing the drapery of the bed closely together. The object is to keep the infant sufficiently warm with pure air; it therefore ought to have free access to its mouth, and the atmosphere of the whole room should be kept sufficiently warm to allow the child to breathe it freely: in winter, therefore, there must always be a fire in the nursery. The child up to two years old, at least, should sleep upon a feather bed, for the reasons referred to above. The pillow, however, after the sixth month, should be made of horsehair; for at this time teething commences, and it is highly important that the head should be kept cool.