View report page

58
would be transmitted through the private drains so
changed, especially in a town of steep gradients.
(6) The large number of instances where the drains
are carried under the houses and the great probability
(especially on a clay subsoil) of the joints of such drains
being defective.
(c) The possibility of the existence of some old sewers
which are not self cleansing and which are otherwise of
faulty construction.
(d) The possibility of disease germs, such as those of
diphtheria or typhoid fever, being transmitted via the
sewer air from the inmates of one household (or possibly
from multiplication of the germs in the sewers) to the
inmates of another household.
Where the modern system of house drainage is universal,
i.e. all gully traps placed outside the house, all waste pipes
intercepted, the water closet traps and connection exposed to
view, all drain pipes which are carried under the houses made
with water tight joints and embedded in concrete, and a full
bore ventilator carried above the eaves of the roof or highest
window opening, there is little or no possibility of any drain or
sewer air finding its way into the house.
If, added to this, all the sewers have a sufficient fall to
remove the sewage at the rate of at least 3 feet per second—
the sewage being thus removed before there is any evidence of
biological action—the question arises is there the necessity for
a double set of ventilating pipes at each house—one for the
house drains and one for the sewer, or by abolishing the intercepting
trap will not the one ventilator answer for both purposes.
Given such favourable conditions as above mentioned, in
the event of abolition of the intercepting trap and the additional
ventilator on the sewer side (even if the latter could by
an Act of Parliament be placed up the side of each house) the
only question remaining is as to the possibility of transmitting
disease germs from one part of the district to another.