But a further object is secured. As the prisoners never see one another, they leave the penitentiary, at the expiration of their punishment, literally unknowing and unknown. In illustration of this fact, the delightful incident is mentioned, that the keeper of the Philadelphia Penitentiary once recognized three persons at the same place, engaged in honest labor, who had been in his custody as convicts, though neither knew the career of the other two. Discharged prisoners are thus enabled to slide back into the community, without the chilling fear of untimely recognition by those with whom they congregated in the penitentiary. They cannot escape the memory of the punishment they have endured; but the brand is not upon the forehead. They are encouraged to honest exertion by the hope of retrieving, on a distant spot and under a new name, the fair character they have lost; while, on the other hand, if evil-minded, they have no associations of the prison to renew, or to stimulate to conspiracy against society. A system of Prison Discipline with these benign features must long ago have commended itself to general acceptance, if it had not been opposed with exceptional ardor on grounds which, though in reality little tenable, are calculated to exercise influence over the ignorance and prejudice of men. The first objection is, that it is productive of insanity, from an unnatural deprivation of society. However just this may be when directed against the Solitary system, it is inapplicable to what is called the Separate system, which does not exclude the idea of society, and, as practically administered at Philadelphia and elsewhere, supplies both society and labor in ample measure. If the prisoner is not indulged with society enough, it is a fault in the administration of the system, and not in the system itself. In the publications of the Boston Prison Discipline Society, elaborate tables have been arranged showing a tendency to insanity in the Penitentiary at Philadelphia; but careful and candid inquiry will demonstrate that these are founded in misapprehension, and will exonerate that institution from such imputation. The highest authorities in medicine have distinctly declared, that the Separate system, if properly administered, with labor and conversation, does not affect the reason. The names of Esquirol and Louis give to this opinion the strongest sanction of science throughout the civilized world. The same conclusion was affirmed with precision and fervor by Lélut, in an elaborate memoir before the Institute of France, and also by the Scientific Congress assembled at Padua in 1843, and at Lucca in 1844.