The genesis of the peculiar frame of mind of these persons is for the most part lost in obscurity, for it is only very rarely that one of these remarkable personalities can be subjected to exact observation. In view of the often great historical importance of these persons, it is much to be wished that we had some scientific material which would enable us to gain a closer insight into the psychological development of their peculiarities. Apart from the now practically useless productions of the pneumatological school at the beginning of the nineteenth century, German scientific literature is very poor in this respect; indeed, there seems to be real aversion from investigation in this field. For the facts so far gathered we are indebted almost exclusively to the labours of French and English workers. It seems at least desirable that our literature should be enlarged in this respect. These considerations have induced me to publish some observations which will perhaps help to further our knowledge concerning the relationship of hysterical twilight-states and enlarge the problems of normal psychology. CASE OF SOMNAMBULISM IN A PERSON WITH NEUROPATHIC INHERITANCE (SPIRITUALISTIC MEDIUM). The following case was under my observation in the years 1899 and 1900. As I was not in medical attendance upon Miss S. W., a physical examination for hysterical stigmata unfortunately could not be made. I kept a complete diary of the séances, which I filled up after each sitting. The following report is a condensed account from these notes. Out of regard for Miss S. W. and her family a few unimportant dates have been altered and a few details omitted from the story, which for the most part is composed of very intimate matters.