4. Cleanliness.
5. Light.

Without these, no house can be healthy. And it will be unhealthy just in
proportion as they are deficient.

[Sidenote: Pure air.]

1. To have pure air, your house must be so constructed as that the outer
atmosphere shall find its way with ease to every corner of it. House
architects hardly ever consider this. The object in building a house is
to obtain the largest interest for the money, not to save doctors' bills
to the tenants. But, if tenants should ever become so wise as to refuse
to occupy unhealthily constructed houses, and if Insurance Companies
should ever come to understand their interest so thoroughly as to pay a
Sanitary Surveyor to look after the houses where their clients live,
speculative architects would speedily be brought to their senses. As it
is, they build what pays best. And there are always people foolish
enough to take the houses they build. And if in the course of time the
families die off, as is so often the case, nobody ever thinks of blaming
any but Providence[8] for the result. Ill-informed medical men aid in
sustaining the delusion, by laying the blame on "current contagions."
Badly constructed houses do for the healthy what badly constructed
hospitals do for the sick. Once insure that the air in a house is
stagnant, and sickness is certain to follow.

[Sidenote: Pure water.]

2. Pure water is more generally introduced into houses than it used to
be, thanks to the exertions of the sanitary reformers. Within the last