In designing the Westchester County Penitentiary and Workhouse, the second ambition realized by the author was to give each prisoner an outside cell. When the plan was first developed, three years ago, the outside cell was much more a matter of controversy than it is at the present time. The inside cell of the American prison is a type peculiar to this country, and its design is based on the principle that the prisoner is to be retained above every other consideration. Consequently our jails have been designed with what has come to be known as “interior cells,” that is, the cells are placed not against the outside walls, but in the center of the building, back to back, separated by a passageway from three to four feet in width, referred to as a utility corridor, in which all the plumbing and ventilating pipes are placed. The space between the outside of the building and the front of the cells is frequently divided by a steel grille forming two long corridors, the outside corridor being called the guards’ corridor, and the inside corridor, next to the cells, the prisoners’ corridor. The object of this division was to protect the guard from the prisoner, for this system is devised on the theory that every jail building must be constructed on the basis of making it safe for the worst possible criminal which might ever get into it. Indeed, every once in a while a guard is killed by a prisoner; but so every once in a while a man is killed crossing the street, but this does not mean that our streets are unsafe, if reasonable care is observed in traversing them. LIGHT, HEAT, AND VENTILATION Placing the cells in the center of the cell block makes it possible to fill the outside wall with windows--in fact, a proportion of light area which came to be established was that the outside wall should be 50 per cent glass. The radiation was placed between the windows, which open like louvres, and with an exhaust fan in the top of the utility corridor it was possible to draw the warm fresh air through the cell to the roof, thereby obtaining very satisfactory results in heating and ventilation. [Illustration: STAIR HALL, ADMINISTRATION BUILDING]