§ 140
If the person cannot write, the physician must be informed by him every day of what has occurred to him, and how it took place. What is noted down as authentic information on this point, however, must be chiefly the voluntary narration of the person who makes the experiment, nothing conjectural and as little as possible derived from answers to leading questions should be admitted; everything must be ascertained with the same caution as I have counselled above (§§ 84-99) for the investigation of the phenomena and for tracing the picture of natural diseases.