In all the prisons, Northern or Southern, enclosed by a fence or a stockade, there was a ‘dead-line,’ or what corresponded to it. Its necessity, from the standpoint of the guard, was obvious. If the inmates were allowed to approach the fence, a concerted rush would result in many escapes. Prisoners were shot on both sides for crossing this danger line, and for approaching or leaning out of the prison windows. Correspondence was restricted as to length and frequency in all prisons, and both incoming and outgoing letters were read by some one detailed for the purpose. Money sent in letters was occasionally abstracted, and not placed to the prisoner's account. After the first year, money was always taken from the prisoners on entering, as it was found that a guard was not always above temptation. When a sutler was allowed in a prison, a prisoner with a balance to his credit was allowed to give orders on his account, or else he was furnished with checks good for purchases. The amount remaining to his credit was supposed to be returned to the prisoner on his release, or to be transferred with him when sent to another prison. The relative mortality in prisons, North and South, has been much discussed, and very varying results have been reached. The adjutant-general of the United States, in 1908, published a memorandum summarizing the results of his investigations.
According to the best information now obtainable from both Union and Confederate records, it appears that 211,411 Union soldiers were captured during the Civil War, of which number 16,668 were paroled on the field and 30,218 died while in captivity; and that 462,634 Confederate soldiers were captured during that war, of which number 247,--769 were paroled on the field and 25,976 died while in captivity.From this it would appear that the mortality in Federal prisons was twelve per cent., while in Confederate prisons it was fifteen and one-half per cent. of the total number confined.