That the inner surface of the walls of every Slaughter-house be covered with slate, stone, or other hard, smooth, impervious material, to the height of 7 feet 6 inches, and that above this height to the roof the walls be cemented. OBJECTION. _The Butchers say, “It is a useless expense to extend the smooth, impervious material beyond four feet,” and that “there is no practical advantage in cementing the whole of the upper part of the walls of the Slaughter-house; on the contrary, the hard bricks are superior to cement, which will break off.”_ REPLY. The height of the “dado” was increased from 4 feet 6 inches to 7 feet 6 inches, in consequence of my having inspected a Slaughter-house outside the City, and finding 4 feet 6 inches insufficient to protect the walls above from the splashing of blood and filth, the “dado” itself being clean. In Edinburgh the walls are formed of solid ashler stone to a height of _seven feet_. The advantage of covering the inner surfaces of the Slaughter-house walls with an impervious cement are twofold: _Firstly_, the walls can be much more easily washed and kept clean. _Secondly_, it obviates the liability of the walls becoming saturated with decaying nitrogenous matter by the constant absorption of moist animal vapours by porous bricks. [This precaution was suggested by a perusal of an account of the practical experiments of Professor Pettenkofer, of Munich, who has clearly demonstrated in various ways the extreme porosity of ordinary brick walls.] _Lastly_, a hard, smooth wall prevents the ingress and lodgment of vermin. The question of expense raised by the Butchers is hardly worthy of prosperous and wealthy tradesmen, and the objection that the cement would “break off” is too frivolous to answer. BYE-LAW VII. That each Slaughter-house be provided with adequate lairage or poundage, separated from the slaughtering space by a closed partition, extending from the floor to the roof, formed of brick, stone, slate, or other similar material, having a smooth impervious surface, to a height of at least 7 feet 6 inches from the floor. That in all cases where from the present plan of the premises a door is needed between the Lair or Pound and the slaughtering space, such door be provided with spring hinges, and be kept closed when not open for the passage of cattle, but that where other means exist of taking cattle from the Lair or Pound into the Slaughter-house, without passing through shops, or over important public ways, no door shall exist between the Lair or Pound and the Slaughter-house. OBJECTIONS.