Green’s Dictionary of Slang

1. a hypodermic syringe.

1925		H. Leverage ‘Dict. Und.’ in Flynn’s mag.
1953		Anslinger & Tompkins Traffic In Narcotics 311: joker. A hypodermic needle.

2. an injection of morphine.

1925		H. Leverage ‘Dict. Und.’ in Flynn’s mag. cited in Partridge DU (1949).
1953		Anslinger & Tompkins Traffic In Narcotics 311: joker. [...] a dose of morphine taken by injection.