"What does Reverence for Life say abut the relations between [humanity] and the animal world? Whenever I injure any kind of life, I must be quite certain that it is necessary. I must never go beyond the unavoidable, not even in apparently insignificant things.
The farmer who has mowed down a thousand flowers in his meadow in order to feed his cows must be careful on his way home not to strike the head off a single flower by the side of the road in idle amusement, for he thereby infringes on the law of life without being under the pressure of necessity."
One of Schweitzer's dilemmas came while in Africa, someone gave him an injured eagle to heal. He had to kill a fish to save the bird.