The Buffet Blue Book by John H. Considine (1912, p.74)

1 glassgin base
2.5 dashAbbott's Bitters — The source suggests 2 or 3 dashes, or as much as desired.bitter
  1. Add Abbott's Bitters to the ordinary drink of gin.
  2. Serve as a simple tonic.

This is presented in the source as a short service note rather than a full formal cocktail recipe.