quently change as his collection of facts and his invention of explanations advance; new facts and new ideas may frequently call for the revision of earlier facts and ideas, and for the change of first-formed opinions; all such revision and change are best accomplished when the student is alone with his problem. At the end of his study, the net results gained may appear to be of small volume, in view of the time and labor spent in reaching them; but if they include a matured and well-balanced judgment on the problem under discussion, as well as an intimate acquaintance with its sources of material, a comprehensive knowledge of its historical development, and a close familiarity with all the factors involved in its investigation, the time and labor will have been well expended.
Presentation.—Occasion then arises for the oral or printed presentation of the results of all this independent work, in form for their best understanding by others. The student must then emerge from his isolation, in which the world may have seemed to him to be occupied chiefly by his problem and himself; he must recognize that the real world is crowded with other problems and other workers, among which he and his interests may be rudely jostled in course of finding the place that they deserve. He must now awake to a realization of his surroundings, and consider particularly what sort of presentation will place his results most effectively and favorably before the public. He no longer has to consider the nature of his own work; that he has done sufficiently already. He has now to consider the nature of other persons whose interests are more or less akin to his own, in order to discover how he can best bring his work before them. When his presentation has been made, he will learn that those of his hearers or readers who meet him with unselfish sympathy and just appreciation become his most helpful and encouraging friends; and he ought at the same time to learn what his own bearing should be when it is his turn to listen to reports by his colleagues on their work. We will here examine briefly the requirements of an oral presentation, postponing the discussion of a printed report to a later page.
When a student rises to make an oral report in the presence of his teachers and his comrades, he is no longer an investigator alone with his problem; he takes his place as a speaker, between his problem and his hearers. There may be cases in which his personal experience deserves narration; but in scientific communications, personal items should, as a general rule, be relegated to the background; the speaker had best try to obliterate personal matters, which always give a more or less subjective flavor to a report, and strive to make himself simply the conduit through which the essence of his subject, in the most objective form, shall flow to the minds of his hearers. He has no longer abundant time, but is limited to half an hour, or an hour at the most; at