"Dr. Heidegger's Experiment" is set in Dr. Heidegger's gloomy and eerie study. There is a lot of imagery in the study-- there is a book of magic, a strange mirror, a portrait of a woman, and a skeleton. It is said that when the book of magic was lifted by a maid, the skeleton rattled, the woman stepped out of the portrait, and the bust of Hippocrates spoke out.
Other imagery includes Dr. Heidegger bringing the wilted, dead rose back to life when he tosses it into his magic water. Also, the guests get very lively after they drink the water. They act young again, dance, and fight.
Symbols include the mirror, the rose, and the portrait of the woman. The mirror, which shows the faces of the doctor's dead patients, seems to be a source of truth. Maybe the dead patients are implying that Dr. Heidegger was a bad physician and he caused their deaths. Maybe Dr. Heidegger is haunted by ghosts. The mirror also reflects the four rowdy guests as their true selves--it shows them old, even when they believe that they are youthful again. The mirror could symbolize truth--even though the guests' outward appearance has changed, they are still morally corrupt inside.
The rose was given to Dr. Heidegger by his lost love Sylvia. Dr. Heidegger values the rose even though it is old and has lost its beauty. The rose might symbolize Sylvia herself. Dr. Heidegger has moved past caring about youth and beauty, and his experiment reveals just how vain his four guests really are.
The portrait of the woman along with the skeleton makes the reader wonder how Sylvia really died. The text says that she swallowed one of Dr. Heidegger's prescriptions and died before they were married. Did she do it on purpose? Did he kill her? The skeleton (like the expression "skeletons in the closet") makes the reader wonder if Dr. Heidegger is keeping a dark secret about his fiance's death.