Mr. Lewis, of the General Board of Health, from his examination of the
contents of nearly 100 coffins in the vaults and catacombs of London
churches, concludes that the complete decomposition of a corpse, and
its resolution into its ultimate elements, takes place in a leaden
coffin with extreme slowness. In a wooden coffin the remains, with the
exception of the bones, vanish in from two to five years. This period
depends upon the quality of the wood, and the free access of air to
the coffins. But in leaden coffins, 50, 60, 80, and even 100 years
are required to accomplish this. “I have opened,” says Mr. Lewis, “a
coffin in which the corpse had been placed for nearly a century; and
the ammoniacal gas formed dense white fumes when brought in contact
with hydrochloric-acid gas, and was so powerful that the head could
not remain in it for more than a few seconds at a time.” To render the
human body perfectly inert after death, it should be placed in a light
wooden coffin, in a pervious soil, from five to eight feet deep.