If a mother, with or without reasonable cause, deputes her duties to a wet nurse, she ought thoroughly to understand that the expedient is not without drawbacks. All the best accoucheurs agree that in choosing a woman for the office, observation of the figure, the complexion, the colour, the teeth, or even the shape and development of the breasts, and the analysis of their secretion, are all unimportant compared with a knowledge of the regularity of the catamenia. In this respect it stands to reason we must take the applicant's own character of herself, a serious temptation to dishonesty. An unmarried woman may not improbably have a concealed constitutional taint, which is communicated through the milk, and at the best is an unpleasant inmate in the family. A poor married woman, however respectable, is removed from a starving home to sudden abundance, and invariably over-eats herself and it is fortunate if she does not over-drink herself too. She pines andgrows anxious about her own child if it is alive, and insists upon having her troublesome husband to see her openly or secretly, on the pretence (a fallacious one) that his visit increases the flow of milk. Moreover, a rich mother cannot but feel some compunction in purchasing for her own offspring what is stolen from another, who is sometimes seriously affected by the fraud, and retires disgusted from this false world.
Thomas King Chambers, A Manual of Diet in Health and Disease, 1876