 Writing on the subject in 1843, physician John Snow concluded that it would have been impossible to conceal thousands of bodies in the space described.He wrote that the vault had a bricked-over barrel sewer rather than the open sewer described by some witnesses, and noted that any sewer would soon have become blocked if used to dispose of the dead.Upon visiting the building Snow could see none of the "crevices" mentioned by Fox, and he described the reports to the committee as having been "a mass of fictitious horrors".