Note 1 — Chapter I

Infancy appears to be the best English term to represent the German Sänglingsalter, literally "age of suckling." It is true that the legal denotation of the term infancy is "the period from a person's birth to the attainment of the age of twenty-one years," but in common speech an infant is "a child during the first two or three years of life," whilst writers on infant mortality restrict the term to the sense employed in the text. Thus Newman, in The Health of the State (p. 108), writes: "Infants are children under twelve months of age."—Translator's Note.