Old Waldorf Bar Days by Albert Stevens Crockett (1931) — Old Waldorf Bar Days 1931, opening cocktail appendix

5 dropAromatic Spirits Ammonia base
1 jiggerwater dilution
  1. Stir and strain.

The Old Waldorf-Astoria Bar Book by Albert Stevens Crockett (1935, p.36)

5 dropsaromatic spirits of ammonia — Aromatic Spirits Ammoniabase
1 jiggerwater dilution
  1. Stir the aromatic spirits of ammonia and water.
  2. Serve as a tonic rather than a cocktail.

Crockett says it is considered a cure rather than a cause.