"Every discoverer of a new truth, or inventor of the method which evolves it, makes a dozen, perhaps fifty, useless combinations, experiments, or trials for one successful one. In the realm of electricity or of mechanics there is no objection to this. But when such rejected failures involve a torture of animals, sometimes fearful in its character, there is a distinct objection to it."
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Source : "Surgical Anaesthesia: Addresses and Other Papers". Pp. 369-370. Book by Henry Jacob Bigelow, 1894.