The following passage is located on page 105 in Women's Lives in Medieval Europe by Emilie Amt:
"When choosing a wet nurse, she ought to be young and have a pink and
white complexion. Let her be not too near to prospective parturition nor
too far removed from preceding parturition. Let her not be dirty. She should
have neither weak nor too heavy teats, but breasts full and generous, and
she should be moderately fat. Let her not eat salt, sharp, acid or styptic
things - leeks, onions, nor the other kinds of things that are mixed with
foodstuffs such as pepper, garlic and colewort. Especially have her avoid
garlic. Let her beware of anxiety and guard herself during menstruation.
If the milk is diminished, let pap be made of bean flour or rice flour
and a bread containing milk and sugar be given to her to eat. The milk
will be increased if a decoction of the seeds of fennel be drunk. If however
the milk becomes thick, the nurse's nourishment will have to made lighter.
Compel her to excercise and she should be given vinegar syrup and light
wines. If the milk becomes too thin let her nourishment be thick and substantial
and have her rest more. If the child's bowels be loose, let foods which
cause constipation be given to the nurse."