The Old Waldorf-Astoria Bar Book by Albert Stevens Crockett (1935, p.144)

to tastebrandy base
1 or moreegg — eggsbase
to tasterum — Jamaica rumbase
to tastemilk dilution
1 gratenutmeg other
to tastesugar sweetener
  1. Shake well, strain, and grate nutmeg on top.

See also: Egg-Nog