E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
the character made thus, & = and. In the old Horn-books, after giving the twenty-six letters, the character & was added, and was called Ampersand, a corruption of and per-se & (and by itself, and). A B C D . X Y Z &.
Any odd shape folks understand
To mean my Protean amperzand.
Punch (17 April, 1869, p. 153, col. 2).
The martyr Bradford, says Lord Russell, was A per se A with them, to their comfort, etc.i.e. stood alone in their defence.