The sanitation of this prison leaves little to be desired. The cells are spacious, wholesome, and well ventilated. Their furniture consists of a hammock suspended from cramp-irons; of a wooden stool, a water-can, and one or two other articles the reverse of luxurious. The ventilation is managed on scientific principles by means of orifices at different altitudes; and so effectual is it that in an experiment which was once made, with three men smoking tobacco in them incessantly for three hours, it was found that the fumes disappeared as fast as they were produced, and that the atmosphere never once lost its transparency. This circumstance is a great consolation for the Mazas prisoners, who can beguile the time with their pipes. As to the interior régime of the prison, the spacious courts which separate each gallery of cells are divided into promenades, in which the prisoners are free to exercise themselves for at least one hour a day. A part of these promenades is provided with a shelter in view of wet weather. The prisoners take exercise by turns, and always alone, the warders being able from certain points of observation to follow their movements incessantly. An infirmary is attached to the prison, as well as bath rooms, which are no less commodious than cleanly. Each prisoner is known at Mazas by the number of his cell, inscribed on a plate hung above the door, and which is turned over to indicate that the prisoner is away from his cell taking exercise or receiving instruction. Among the special punishments inflicted on the more serious offenders are: exclusion from outdoor exercise, a diet of bread and water, a bare plank bed, and a dark cell. The administrative and subordinate staff of the Mazas consists of a director, four registration clerks, a brigadier, four sub-brigadiers, sixty-four warders, a laundress, three chaplains, a doctor, a chemist, a female searcher, two barbers, and four commissioners, not to mention some three dozen prisoners employed as assistants. What chiefly strikes a visitor to the place is the regular and geometrical plan on which the whole prison is constructed. The arrangements are of the most perfect description, though it was complained some years since that the method of arranging divine service--the door of each cell being kept ajar, so that the prisoner can see the altar and the officiating priest--provided to a large part of the prisoners little more than a curious spectacle. * * * * *