Many builders in the Littleport Fens until c.1910, regularly fetched blood from the butchers, recalled W.H. Barrett, and used this to mix the mortar to be used on the brickwork of chimneys and hearths. Some of them did this with the, by then, vague idea of bringing good luck to the future occupants of the house, but several, including his uncle, were of the definite opinion that the blood would be a safeguard against witchcraft. Salt-glazed bricks were often used, with the same purpose in mind, for building chimneys.