This is a lecture given by Carl Jung at the First International Congress of Psychiatry and Neurology, Amsterdam, September 1907. It was first published a year later in Monatsschrift für Psychiatrie und Neurologie in Berlin in 1908. In this lecture, Jung attacks Freud's theories around Hysteria and sexuality, especially his theories of developmental sexuality. This was one of the works that led to Freud's break from Jung. This new translation aims to make these early scientific works by Jung (which were designed to be read by academics) to be easily read by today's modern reader, with the academic references removed and the language clear and simple.