Those giant testes could be found in many drugstore windows - you saw those tanks of colored water, and you knew you could get some drugs inside. Not the best drugs, since they hadn't been invented yet, but drugs enough for the needs of the moment..
But why? According to this page, "Show globes" demonstrated the skils of the pharmacist, since he could use various techniques to color or layer the fluid; they also showed he wasn't a fly-by-night type, since he had invested a lot of money in show globes.
You don't see them any more, so no one knows what they mean nowadays. Another small detail of the past you wouldn't get if you were pitched back in time 70 years.