The Island of Dr. Moreau
How we cite our quotes:
"This store men and women set on pleasure and pain, Prendick, is the mark of the beast upon them, the mark of the beast from which they came." (14.26)
Suffering comes from the fact that we are animals. When we don't get life necessities or when we damage our bodies, nature uses pain and suffering to tell us, "Hey, stop doing that!" It's a shame then that empathy, the emotion that lets us know we are hurting others, is not natural.
"Each time I dip a living creature into the bath of burning pain, I say: this time I will burn out all the animal, this time I will make a rational creature of my own!" (14.41)
Meet Moreau in full-on mad scientist mode. He still recognizes pain for what it is, the nerves responding to bodily damage. But it's left him blind to the suffering of said pain. In the mad scientist cocktail, this type of ambition is a key ingredient.
When I heard that, I forgave the poor wretch all the fear he had inspired in me. (16.83)
Leopard Man has caused Prendick to suffer (more mentally than physically). However, seeing Leopard Man's own fear and suffering, Prendick has a moment of empathy and can forgive the creature. An empathy epiphany, if you will (sorry, but we're total word nerds here at Shmoop, and this kind of stuff makes us giggle).