"Y: Do you include those animals which are guilty of the same crime themselves by living on prey? Should we not then save a thousand lives by killing one? Z: We must never suppose a person or an animal guilty until they are found in the act, and then we must investigate the nature of the crime. It is true that the animal living by slaughter may be less entitled to our consideration than the animal which is harmless; but recollect, the former may plead the same excuse itself, unless his slaughter be only of those animals which live on vegetables; and then, though justice may require their destruction, it would be repugnant to the feelings of humanity to slaughter them with that plea, unless we could quite assure our conscience that our design in killing them was more to prevent their doing mischief than for our own benefit: besides, we might then extend this principle still further, and kill our own species because they are also animals of prey. It is moreover to be observed, that if one carnivorous animal kills another, he may save lives by it also, and the nature of the act will be different according to circumstances [...] And, further, it will frequently be impossible to discover when the animal becomes guilty or innocent, as it depends on such a variety of circumstances: we should therefore be more safe from infringing the laws of moral rectitude, not to interfere in this case."