A healthy mother is fully capable of furnishing this quantity of milk per day, and of affording the child all the nourishment it needs until four or six months after birth. The quantity of the mother's milk varies according to many circumstances. It is most abundant and also most nutritious in nursing women between the ages of fifteen and thirty; least so, in those from thirty-five to forty. There is likewise a great difference in different women in this respect; and in the same woman varying conditions of health influence the amount of milk secreted. THE QUALITIES OF A GOOD NURSING MOTHER are well described by Professor J. Lewis Smith. 'The best wet-nurses are usually robust, without being corpulent. Their appetite is good, and their breasts are distended, from the number and large size of the blood-vessels and milk-ducts. There is but a moderate amount of fat around the gland, and tortuous veins are observed passing over it. Such nurses do not experience a feeling of exhaustion, and do not suffer from lactation. The nutriment which they consume is equally expended on their own sustenance and the supply of milk. There are other good wet-nurses who have the physical condition described, but whose breasts are small. Still the infant continues to suck till it is satisfied, and it thrives. The milk is of good quality, and it appears to be secreted mainly during the time of suckling. Other mothers evidently decline in health during the time of nursing. They furnish milk of good quality and in abundance, and their infants thrive; but it is at their own expense. They themselves say, and with truth, that what they eat goes to milk. They become thinner and paler, are perhaps troubled with palpitation, and are easily exhausted. They often find it necessary to wean before the end of the usual period of lactation. There is another class whose health is habitually poor, but who furnish the usual quantity of milk without the exhaustion experienced by the class just described. The milk of these women is of poor quality. It is abundant, but watery. Their infants are pallid having soft and flabby fibre.' OVER-ABUNDANCE OF MILK. An excessive amount of milk often distends the breasts of those women who are prone to have long and profuse monthly sickness. It is also apt to occur in those subject to bleeding piles. It may be produced by any excitement of the womb or ovaries, and by over-nursing. In these cases there is usually a constant oozing away and consequent loss of milk. The mother is troubled by this over-flow, because it keeps her clothing wet; and the child suffers because of the unnutritious, watery character of the milk under such circumstances.