Two methods are in use abroad for ventilating the outside cell, but neither is adequate. The English way is to build in the front wall of the cell a panel of special bricks which are made with diagonal or curved openings which will let the air through, but which will not permit the prisoner to see through. This arrangement is intended to ventilate the cell into the central corridor; but the central corridor is usually quite as much in need of ventilation as the cell itself. In the majority of English prisons the cell blocks are four tiers high, the cells being on the outside walls reached by galleries with the central corridor running clear through from main floor to roof. This is always bad, as such interior spaces can only be lighted and ventilated through the roof; and while overhead lighting is always questionable, overhead ventilation is still more so. This condition is made worse as the cell block increases in length, and some of them, as at Pentonville, I think, are 175 feet long. This method of reaching the cells from galleries came about as a means of facilitating supervision, for the guard standing on the main floor has a view of all the inmates as they come out of their cells. As a matter of fact, the top galleries have very little supervision owing to their distance from the guard’s station. Better supervision is had and better discipline maintained when the cell floors run through, for then a guard may always be on the same floor with the prisoner. This arrangement also makes for better classification and greater quiet throughout the cell block. [Illustration: CELL BLOCK CORRIDOR] On the Continent, and in some of the older English prisons, the cells are ventilated by ducts or flues built in the walls, each cell with its separate flue, the registers of which are sometimes controlled by the guard from the corridor, but usually by the prisoner from the cell. The results of this method of ventilation, however, did not seem satisfactory to the author on the chilly February days when he was in Holland and Germany, for without exception he found the cell windows shut, in spite of the prison rules requiring that the prisoner shall always keep his window open.