There is yet another method by which perhaps we may test the morality of the practice. A great philosopher of another century seeking to find some criterion of man's duty toward his fellow-men, based obligation upon a universal law. "Act," said Kant, "as if the motive of thy conduct were to become by thy will a universal law." Suppose we apply this maxim of Kant to the use of human beings for research purposes. An experimenter in a hospital makes dying children his material. Is he willing that the maxim of his act should be universal, and apply to experiments upon his own child, when it lies at the point of death? He plunges needle-electrodes into the brain of a simple-minded and perhaps friendless servant-girl. Can we imagine him willing that the motive of his deed should govern and justify experiments of the same kind made upon his mother or his wife? Following Ringer, he tests the actions of poisons upon patients in some hospital under his control. Would he be willing that the law be universal, and that the action of such drugs should first be tested upon himself? He suggests the use of healthy children as "controls" in tests with the dead germs of a horrible disease. Is there anyone connected with the Rockefeller Institute, for example, who would be willing that such act should establish a universal precedent, and that his own children should be taken, and without his knowledge, made the "material" for such research? Admitting that some experiments upon human being may be ethically permissible, and that other phases of such investigations are morally wrong, how are we to distinguish between them? May it not be possible to indicate principles which would be generally accepted, according to which the line may be drawn? Let us make the attempt. I. Justifiable Experimentation upon Man 1. All experiments made by intelligent and conscientious physicians or surgeons upon their patients for some definite purpose pertaining to the personal benefit of the patient himself, and when practicable, in case of risk, with his or her consent. (This rule is intended to include every possible experiment made by a medical practitioner for the benefit of the patient, with a distinct ameliorative purpose in view.) 2. All experiments made with an intelligent purpose by a scientific man or medical practitioner upon himself. 3. All experiments made with their consent upon physicians, surgeons, pathologists, medical students or other scientific men, who, aware of the nature of the investigation and of possible results, voluntarily offer themselves as "material." 4. All experiments made upon men or women of ordinary intelligence who, having been fully informed of the nature of the investigation and of whatever distressing or dangerous consequences are obviously liable to result, acknowledge the receipt of satisfactory compensation for all risks, and give in writing their full and free consent.