| Quote #1
Over the central bookcase was a bronze bust of Hippocrates, with which, according to some authorities, Dr. Heidegger was accustomed to hold consultations in all difficult cases of his practice. (3)
Among other medicinal developments, Hippocrates was famous for separating religion and superstition from the realm of medicine. Heidegger's claim that the water is from the Fountain of Youth has a touch of irony, then.
| Quote #2
In the obscurest corner of the room stood a tall and narrow oaken closet, with its door ajar, within which doubtfully appeared a skeleton. (3)
The "skeleton in the closet" is a metaphorical phrase that refers to a secret someone wants to keep hidden. That Dr. Heidegger literally has a skeleton in his closet is not just creepy, but also a testament to the narrator's sense of humor.
| Quote #3
Between two of the bookcases hung a looking-glass, presenting its high and dusty plate within a tarnished gilt frame. Among many wonderful stories related of this mirror, it was fabled that the spirits of all the doctor's deceased patients dwelt within its verge, and would stare him in the face whenever he looked thitherward. The opposite side of the chamber was ornamented with the full-length portrait of a young lady, arrayed in the faded magnificence of silk, satin, and brocade, and with a visage as faded as her dress. Above half a century ago, Dr. Heidegger had been on the point of marriage with this young lady; but, being affected with some slight disorder, she had swallowed one of her lover's prescriptions, and died on the bridal evening. (3)
It appears that Dr. Heidegger is not the most adept of doctors if 1) he has all these dead patients, and 2) his fiancée is dead on account of taking one of Heidegger's prescriptions.