an _improper way_, from approaching those questions, and using those methods, that lead to the discovery of truth, and from acknowledging the results it has found to be true; or which would unlawfully keep it from making known, for the benefit of others, the results of its investigation. It should be free from any unjust restriction, imposed by state or Church, by popular opinion, by party spirit, by hampering protectorate, or servility of any kind. From any _unjust_ restriction, we said. For this is clear: if under certain circumstances there might be warrant for a _just_ restriction by external authority, such a restriction could not be refused in the name of freedom. So long, then, as we understand by freedom a _lawful_ freedom, there cannot be included in this the freedom from _every_ external authority, but only from _unlawful_ interference. There is, then, the question whether there may be a legitimate restraint, imposed by external authority, which man must not evade, and what the nature of such restraint may be. We must, moreover, take into consideration two elements, which are distinguished in the above definitions, both belonging to the modern idea of scientific freedom. We will call them _freedom of research_, and _freedom of teaching_. The investigator and the scientist claim the one; the teacher, the other. Searching after truth, and communicating the truth found, are, as is known, the principal occupations of science. The scientist should first of all be an investigator. He should not be content to appropriate to himself the knowledge of others, he should also make his own additions to knowledge. He is also commonly a teacher, by word of mouth, as at the university, or by his writing, in his literary activity. Research, as such, imparts directly a certain knowledge only to the investigator; it is of a private nature and as such does not reach beyond him. But by teaching, his ideas are communicated to others, and then begin to influence their thought, will, and action, often very strongly. Teaching is a social factor; with it are bound up the weal and woe of others. Suppose a man of influence conceives in his study the idea that monogamy is an infringement upon the universal rights of man; should he be given without any ado the right of disseminating, by teaching, the imagined results of his investigation, to the confusion of men, and with serious danger to the peace of society?