DRAINAGE. 195 



the ground of the interior and immediate vicinity of a stable 

 in a dry condition, its surface should as far as possible be 

 waterproof, and its drainage should be of the horizontal 

 kind, for which a difference of level is required. Hence, it is 

 advisable to have the floor of the stable raised, say, 6 to 9 

 inches above the surface of the ground surrounding it. 



When drains outside the stable are required, care should be 

 taken that while they efficiently serve their purpose, no 

 effluvium from them will have any chance of contaminating 

 the air breathed by the horses. 



The question of subsoil (covered) drains which open inside 

 the stable is chiefly one of labour. With an exception to 

 which I shall presently allude, they are objectionable ; because 

 they tend to render the place unsanitary by the foul gas and 

 damp emitted from them, and because they necessitate a slope 

 being given to the surface upon which the horses stand. A 

 common form of drainage which combines both these dis- 

 advantages, is one in which a drain runs down the centre of 

 a line of stalls, into which it opens by means of grates ; 

 the floors of the different compartments being made to slope 

 towards their respective grates. Owing to the presence of the 

 horses' litter, especially if peat moss, tan, or sawdust be used, 

 this drain is liable to become blocked up, and when in that 

 condition is more apt than ever to give off unhealthy stenches 

 and vapour. Besides, as the urine will then be unable to 

 escape by means of the drain, it will probably accumulate 

 under the horses. The objection as to contamination of air 

 and flooring by this system of drainage can be more or less 

 removed, if there be a free supply of water, by having, 

 instead of grates, the openings of these drains provided with 

 blocks of stone or other convenient material, so as to keep 

 them hermetically closed, except when it is required to sluice 

 out the drain, on which occasions the blocks can be taken up 

 and afterwards replaced. 



13* 



