An exhaustive study of the role salt played in the drama of the War Between the States   It is only when a prime necessity thrusts itself upon public attention by its absence that a person ceases to take it for granted. Only when he no longer has it, does he realize what an important ingredient for his palate and digestion is plain, ordinary salt, necessary alike for man and beast. He then recalls that the salt licks and salt springs have from the earliest times been centers of interest and development.   The author has searched into the archives of most of the states of the old confederacy, and also into departments of knowledge remote from her own, so that she has had to delve into geological libraries, consult colleagues in the fields of chemistry and physiology, and do more sums in arithmetic than have fallen to her lot since she was in the primary school. But it has been a pleasant and profitable search.