And this is the moment which has been chosen for striving to arrest the march of Science: when epidemic disease, such as the plague and cholera, is checked; tuberculosis half-conquered; diptheria rendered inoffensive; operations become almost harmless; cancer on the eve of being understood and subjugated! And are we to stop there? Are we not to seek to fathom the many problems still waiting to be solved, and on which depend the lives of so many human beings, and so much human happiness? Do you believe that Science has come to an end? Certainly we already know a great deal; but what we know is as nothing compared to what we do not know. An immense domain of unknown truths lies open to our activity. And we are able to forsee what inexpressible benefits these new truths will scatter over suffering humanity. Consequently, everyone, every man enamoured of goodness and justice, should be filled with respect for Science, and set all his hopes on her. At the same time, however great may be my adoration for Science, it must not be at the expense of human personalities, or, let us say it distinctly, at the expense of animal personalities, which although uncertain and indistinct, still merit a share, and a large share, of justice and of pity. As for human personalities, without the slightest doubt, we have not the right to sacrifice an innocent creature for Science. Every human being ought to be treated with respect, and we have not the right to kill and martyrise a human being even if his death and his martyrdom might serve the cause of Science. As for animal personalities, the question becomes much more doubtful. For inferior beings with indistinct consciousness, and, without a doubt powerless to perceive pain, no scruple should hold us back. But if it concerns beings nearer to ourselves, such as monkeys, cats, dogs, horses, all certainly capable of feeling pain, we must be chary of inflicting pain, and experiment only after having totally abolished in them all sensation of pain. But under penalty of falling into fetishism, we must not fear to use the life of these beings in order to prolong the life of man. Every time we propose to make an experiment, it is as though we put this question to ourselves: is this dog worth more than a man? or than a hundred men? or than the whole of humanity to come? Thus put, the problem bears only one solution: Avoid giving pain to the animal on condition that it is not at the cost of innumerable human pains. Moreover, it is the same here as in every question we may wish to investigate: Each of the two adversaries set out from a just principle, incontestably just. But each one pushes the just principle so far that he ends by transforming it into a colossal absurdity.