374 



VETEEINAEY HYGIENE 



by the removal of the bell, and deserves the name applied 

 to it of ' the domestic air poisoner.' No trap can be effective 

 the trapping system of which is under control. 



Traps used in the interior of stables require special con- 



Fig. 159.— Ventilating Syphon. Kg. 160. — Access Syplion. 



struction to prevent bedding finding its way into and 

 blocking the drain ; to prevent this a perforated tray is fre- 

 quently introduced as in Figs. 162 and 163. Besides bedding, 



TO^ 



Fig 161.— A Simple Syphon Fig. 162.— The Bell Trap. 



sand and gravel find their way into the trap, and provision 

 has to be made for catching these and similar obstructions ; 

 this can be done by means of a movable bucket placed at 



Fig. 163 —Section of a Stable Trap 

 with a Fixed Syphon and Tray. 



The Exterior of Fi 



the bottom of the trap, which can be taken out and emptied 

 without interfering with the trapping arrangements. Good 

 specimens of this trap are seen in Figs. 164 and 165. 

 The ordinary Gully Trap (Fig. 166) is an efficient 



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