“Take one drop at lunch and another at dinner.”
“Yes, sir, but where am I going to get lunch and dinner?”
(O Malho, Rio de Janeiro, 1918) (I might have missed the idiom in the title.) (A later German cartoon with a similar motif.)

A nearly identical Soviet cartoon aimed at contemporary Germany:
“Are you taking the medicine daily after lunch?”
“I take it after the lunch bell, Herr Doctor: we don’t have lunch every day.”
(Krokokil, Moscow, 1936)