We are gratified with such clear and unequivocal testimony to the safety of convict-separation; for we look upon the resort to out-of-door exercise, in special cases, as so perfectly practicable and so entirely in keeping with the principle of the system, that we could scarcely reckon it as a condition or exception. It is of the same character with a precaution respecting air, apparel, bathing, &c. Indeed we do not suppose Dr. G. himself has a particle of doubt, that all needful out-of-door exercise can be given to every convict whose health requires it, as easily and as consistently with the most rigid separation as an extra blanket, or a new article of diet. It will be observed that in the extract just made from Dr. G.’s report, the _second_ year of imprisonment is designated as that in which the bodily and mental vigor of convicts generally begins to decline, and he also mentions those whose sentences range from two to ten years, as “requiring to be closely watched.” From which we infer, that in his opinion there is little danger to be apprehended from the _first_ year’s seclusion; that in the _second_ year there is no danger to be apprehended to the great mass of prisoners, but only to those who have “not sufficient mental vigor to resist the enervating tendencies of the discipline,” and who generally begin at that period to decline in body and mind; and as to convicts whose “sentences range from two to ten years, they should be closely watched,” &c. Our general impression of the weight of authority on this subject, at home and abroad, would coincide with the opinion here expressed; but upon turning to the fable which is annexed to Dr. G.’s report we find, to our surprise, that in seven of the eight insane cases of 1851, the average period of prison-life at which the disorder appeared, was less than eight months; viz., one at four months, one at five, one at seven, one at eight, two at ten, and one at eleven months. In the eighth case the development of disease was postponed for three years and more! Only two of the eight were minors; five were whites, two mulattoes, and one black.