More trivia. Howie erases the blackboard in the schoolhouse pretty quickly but before he does, we see some lines written on it. Here is what they said:

The Cock-Knee Stone preserves the pith of the milk.
The Snail Stone preserves the eyes from the darkness.
The Toad Stone preserves the newly born from the weird woman.
The Hag Stone preserves people from nightmare. (sic. singular in the book, screenplay and movie)