and cared for. Several phrases in this sentence will bear a little amplification.
In the first place, it must be clearly understood that the fixtures and pipes which form an individual system of house-drainage are only a part of the apparatus required for the disposal of offensive and dangerous refuse. Their external connections are
Fig. 2.
an important part of this system, and, according to whether these be with cess-pools or sewers, or whether these last are isolated or are connected with many other houses, will depend the perfection of the results obtained. In this article the house-drains and fixtures only will be considered.
Secondly, what is a "sufficient degree of safety"? Absolute safety can not be guaranteed by any system. If we can so arrange the plumbing that, so far as it is concerned, the air in the house shall be as pure and as free from specific causes of disease as the air in the streets, it is the best that can be done. Reasonable cost refers to that which is essential, and not to that which is
