AS for _Houses_, the first Care ought to be to keep them _clean_: for as _Nastiness_ is a great Source of _Infection_, so _Cleanliness_ is the greatest Preservative; which shews us the true Reason, why the _Poor_ are most obnoxious to _Contagious Diseases_. It is remarked of the _Persians_, that though their Country is surrounded every Year with the _Plague_, they seldom or never suffer any Thing by it themselves: and it is likewise known, that they are the most _cleanly_ People of any in the World, and that many among them make it a great Part of their Religion to remove _Filthiness_ and _Nusances_ of every Kind from all Places about their Cities and Dwellings[91]. BESIDES this, the _Arabians_ advise the keeping Houses _cool_, as another Method of their _Purification_, and therefore, to answer this End more fully, they directed to strew them with _cooling_ Herbs, as _Roses_, _Violets_, _Water-Lilies_, &c. and to be washed with _Water_ and _Vinegar_: than all which, especially the last, nothing more proper can be proposed. I think it not improper likewise to _fume_ Houses with _Vinegar_, either alone or together with _Nitre_, by throwing it upon a _hot Iron_ or _Tile_; though this be directly contrary to what modern Authors mostly advise, which is to make Fumes with hot things, as _Benzoin_, _Frankincense_, _Storax_, &c. from which I see no reason to expect any Virtue to destroy the Matter of _Infection_, or to keep particular Places from a Disposition to receive it; which are the only things here to be aimed at. The _Smoak_ of _Sulphur_, perhaps, as it abounds with an _acid Spirit_, which is found by Experience to be very _penetrating_, and to have a great Power to repress _Fermentations_, may promise some Service this way. AS hot Fumes appear to be generally _useless_, so the Steams of _Poisonous Minerals_ ought to be reckoned _dangerous_: and therefore I cannot but dissuade the use of all _Fumigations_ with _Mercury_ or _Arsenic_. Much less would I advise, as some have done, the wearing _Arsenic_ upon the _Pit_ of the _Stomach_ as an _Amulet_: since this Practice has been often attended with very ill Consequences, and is not grounded upon any good Authority, but probably derived from an Error in mistaking the _Arabian_ Word _Darsini_, which signifies _Cinnamon_, for the _Latin de Arsenico_, as I have formerly shewn[92].