Iron, it is argued, was deemed impure.

No one could make use of it, even for the basest needs of daily life, without incurring a taint prejudicial to the soul both in this world and the next.

But the impurity of any given object never sufficed to prevent the employment of it when required.

Pigs also were impure; yet the Egyptians bred them.

They bred them, indeed, so abundantly in certain districts, that our worthy Herodotus tells us how the swine were turned into the fields after seed-sowing, in order that they might tread in the grain.