1.  That the places of deposit be sufficiently removed from inhabited buildings to prevent any smell being perceived by the occupants. 2.  That the places of deposit be above the level of the ground—­never dug out of the ground.  The floor of the ash pit or dung pit should be at least six inches above the surface level. 3.  That the floor be paved with square sets, or flagged and drained. 4.  That ash pits be covered. 5.  That a space should be paved in front, so as to provide that the traffic which takes place in depositing the refuse or in removing it shall not produce a polluted surface.

In towns those parts of the refuse which cannot be utilized for manure or otherwise are burned.  But this is an operation which, if done unskillfully, without a properly constructed kiln, may give rise to nuisance.  One of the best forms of kiln is one now in operation at Ealing, which could be easily visited from London.

The removal of excreta from houses.—­The chief object of a perfect system of house drainage is the immediate and complete removal from the house of all foul and effete matter directly it is produced.  The first object—­viz., removal of foul matter, can be attained either by the water closet system, when carried out in this integrity; but it could, of course, be attained without drains if there was labor enough always available; and the earth closet or the pail system are modifications of immediate removal which are safe.  Cesspools in a house do not fulfill this condition of immediate removal.  They serve for the retention of excremental and other matters.  In a porous soil it endangers the purity of the wells.  The Indian cities afford numerous examples of subsoil pollution.  The Delhi ulcer was traced to the pollution of the wells from the contaminated subsoil; and the soil in many cities and villages is loaded with niter and salt, the chemical results of animal and vegetable refuse left to decay for many generations, from the presence of which the well water is impure.  There are many factories of saltpeter in India whose supplies are derived from this source; and during the great French wars, when England blockaded all the seaports of Europe, the First Napoleon obtained saltpeter for gunpowder from the cesspits in Paris.  Cesspools are inadmissible where complete removal can be effected.  Cesspits may, however, be a necessity in some special cases, as, for instance, in detached houses or a small detached barrack.  Where they cannot be avoided, the following conditions as to their use should be enforced: 

1st.  A cesspit should never be located under a dwelling.  It should be placed outside, and as far removed from the immediate neighborhood of the dwelling as circumstances will allow.  There should be a ventilated trap placed on the pipe leading from the watercloset to the cesspit. 2d.  It should be formed of impervious material so as to permit of no leakage. 3d.  It should be ventilated. 4th.  No overflow should be permitted from it. 5th.  When full it should be thoroughly emptied and cleaned out; for the matter left at the bottom of a cesspit is liable to be in a highly putrescible condition.