"The event on which this fiction is founded has been supposed, by Dr. Darwin and some of the physiological writers of Germany, as not of impossible occurrence."

- P.B. Shelley, 1818

Click. Click. Click. The rat's paw repeatedly taps the lever in front of it. Click. Click. Click. Each lever strike produces a surge of pleasure in the animal's brain; every "click" is a hit of cocaine in this animal-style drug addiction.

"It is an open question whether it is wise to occupy oneself with many different lines of research. Certainly this variety gives one a broader point of view and is valuable as a background for teaching. Probably the same methods are not suitable for all, but I have noticed that those who stick to a single subject are apt to attain a rigidity of mind which may give a comfortable assurance of competence, but does not permit much originality."