Since coming to the United States I have had the valuable experience of realizing that the conceptions of schizophrenia are very different here from those held in our clinic at Burghölzli. In the following pages I shall try to emphasize the points of difference and to cover briefly the views held in common here and in Switzerland. My father considered it an important step in the understanding of schizophrenia to separate the primary from the secondary symptoms. His purpose was to discover, among the confusingly large number of schizophrenic signs described by Kraepelin, the ones that were present in every case and had to be regarded as the basic difficulties from which the secondary signs developed. This development of the secondary signs on the structure of the primary lesions he considered as due to normal environmental irritations and to normal psychologic and physiologic mechanisms. For the sake of clarity, this