The advantage of feeding from the breast of a wet-nurse is that the mother's milk is substituted by the milk of another woman; in other words, that natural feeding is continued - a matter of moment in all cases, and of inestimable importance with delicate children. The disadvantage consists in the difficulty of finding, in a woman belonging to the class from which wet-nurses come, all the moral and physical characters essential to a good substitute, and the fact that a stranger is introduced into the household, often to deceive and annoy the family, and on the slightest provocation to leave her charge to fate or to the tender mercies of another of her kind. For these reasons it is preferable, in the majority of instances, to trust to careful bottle-feeding. Nevertheless, as some children must have human milk if their lives are to be saved, the rules for selecting a wet-nurse must be understood.

The woman chosen must be strong and robust, but rather spare than fat. Her bill of health must be perfectly free from hereditary tendency to mental or physical disease and from taint of syphilis or tuberculosis. She must be cheerful, good-natured, active, careful, and temperate in habits. Her age should be between twenty and thirty years; she should understand the care of an infant and the manner of giving suck; her child ought to be of nearly the same age as the infant to be adopted, and she must be able to afford an abundant supply of good milk.

The last quality can be estimated by inspecting the breast, by examining some of the milk drawn by a pump, and by ascertaining the condition of the woman's own child. The breasts of a good nurse are not necessarily large, but are firm to the touch and pyriform in shape, with well developed, prominent nipples, and with the skin distinctly marbled with large blue veins. The milk, which ought to flow readily on pressure or on suction, should be opaque and dull white in color, have a specific gravity of 1.031, an alkaline reaction, show, when placed under the microscope, a number of minute, equal-sized, fat globules, and yield on analysis a normal percentage of fat, proteids and sugar. Its quantity may be ascertained by weighing the child before and after sucking, the normal gain being from three to six ounces. There is, however, no better or more readily applied test of the quality of a nurse than the size, weight, and general development of her own child; and if it be weak and ill-nourished, no amount of fitness in other respects can warrant her engagement.

Even when a woman is found fulfilling in her single person all the required conditions - a rare thing, indeed - it does not necessarily follow that her milk will suit the baby to be suckled. Then changes and new trials must be made until the desired end be attained.

The diet of a wet-nurse and the manner of weaning must be governed by the rules already given for maternal feeding.

Personally, I have had such good results from carefully regulated bottle feeding that I have, as far as possible, given up the emloyment of wet-nurses, preferring to regulate the artificial food myself rather than allow an ignorant woman to supplement surreptitiously her deficient supply of breast milk by an unskilfully proportioned food - an event of not uncommon occurrence.