Third Degree Cocktail

Harry of Ciro's ABC of Mixing Cocktails by Harry of Ciro's (1923, p.84) — Harry of Ciro's 1923

1. Shake well and strain into old-fashioned whisky glass.

This matters because it preserves a heavily absinthe-seasoned Plymouth branch late in the London hotel-bar sequence.

Serving it in an old-fashioned whisky glass rather than a stemmed cocktail glass is the noteworthy service detail here.

Barflies and Cocktails by Harry McElhone and Wynn (1927, p.79) — Barflies 1927

1. Shake well and strain into an old-fashioned whiskey glass.

This matters because it preserves a very absinthe-led Plymouth aperitif branch rather than only the milder Martini/Tuxedo family line.