Strange Case of Dr. Jekyll and Mr. Hyde
How we cite our quotes:
My provision of the salt, which had never been renewed since the date of the first experiment, began to run low. I sent out for a fresh supply and mixed the draught; the ebullition followed, and the first change of colour, not the second; I drank it and it was without efficiency. You will learn from Poole how I have had London ransacked; it was in vain; and I am now persuaded that my first supply was impure, and that it was that unknown impurity which lent efficacy to the draught. (10.27)
Although Dr. Jekyll is a scientist, he fails to understand fully how his potion works. Perhaps the nature of mankind is beyond the grasp of science.