Spittle among the ancients was esteemed a Charm against all kinds of fascination: So Theocritus,

And thus Persius upon the custom of Nurses spitting upon Children:

Spitting, according to Pliny, was superstitiously observed in averting witchcraft and in giving a shrewder blow to an enemy. Hence seems to be derived the custom our Bruisers have of spitting in their hands before they begin their barbarous diversion, unless it was originally done for luck's sake. Several other vestiges of this superstition, relative to fasting Spittle, mentioned also by Pliny, may yet be placed among our vulgar customs.

The boys in the North of England have a custom amongst themselves of spitting their faith (or, as they call it in the northern dialect, "their Saul," i.e. Soul), when required to make asseverations in matters which they think of consequence.

In combinations of the colliers etc., about Newcastle-upon-Tyne, for the purpose of raising their wages, they are said to spit upon a stone together, by way of cementing their confederacy. Hence the popular saying, when persons are of the same party, or agree in sentiments, that 'they spit upon the same stone.'

Probably this use of spittle is one of the few remainders left to us from a whole body of scatological rites, now happily dispensed with. A writer in Notes and Queries in 1868 says:-

This must have been a coincidence, for there is no trace of such a custom as spitting on passing a parson. The superstition was rather in the cleric than in the mechanics.