John Augustine Waller, A Treatise on the Incubus, or Night-Mare…
“ I have always observed in my own case, as well as in all those I have had the opportunity of investigating, that this kind of affection is universally accompanied with a sensation called shivering; not precisely of that kind which accompanies the paroxysm of ague, but that momentary sensation of shivering which people are apt to feel on hearing any tale of horror related, or frequently indeed, without any evident cause whatever. It is a vulgar opinion, that this shivering takes place whenever any one is walking over the future grave of the person who feels it. ”
