Midway through Dracula, Stoker makes the following references in regards to extraordinary vigor and longevity:
There are always mysteries in life. Why was it that Methuselah lived nine hundred years, and ‘Old Parr’ one hundred and sixty-nine, and yet that poor Lucy, with four men’s blood in her poor veins, could not live even one day? For, had she lived one more day, we could save her. Do you know all the mystery of life and death? Do you know the altogether of comparative anatomy and can say wherefore the qualities of brutes are in some men, and not in others? Can you tell me why, when other spiders die small and soon, that one great spider lived for centuries in the tower of the old Spanish church and grew and grew, till, on descending, he could drink the oil of all the church lamps?“
The biblical story doesn’t really warrant investigation, and Thomas Parr is established cryptoanthropology, but I was curious about the spider anecdote. A little research turned up the following in the "Literary and Scientific Intelligence” section of an 1821 number of the Edinburgh Magazine and Literary Miscellany:
Spiders.—The sexton of the church of St Eustace, at Paris, amazed to find frequently a particular lamp extinct early, and yet the oil consumed only, sat up several nights to perceive the cause. At length he discovered that a spider of surprising size came down the cord to drink the oil. A still more extraordinary instance of the same kind occurred during the year 1751, in the Cathedral of Milan. A vast spider was observed there, which fed on the oil of the lamps. M. Morland, of the Academy of Sciences, has described this spider, and furnished a drawing of it. It weighed four pounds, and was sent to the Emperor of Austria, and is now in the Imperial Museum at Vienna.“
It appears Dr. Van Helsing was exaggerating the length of the spider’s life somewhat, but the anecdote is at least based on what appear to be real events.
The drawing appears to be lost, unfortunately, though here is an image (Prout, 1839) of the cathedral in question, which appears capable of housing such an animal: