But Herbart’s pupils have done no further work in the province pointed out by him. It is true, his psychology has been made use of by physicians like Griesinger and Spielmann, and recently also to some extent by Krafft-Ebing, but the works of these men have had no influence on the psychological text-books of the Herbartian school, and consequently the science has up to the present day exerted no noticeable influence on pedagogy, either in Waitz, in Stoy, or in Ziller. In other pedagogic schools, this has, it is true, also been the case; but in these, who make no pretensions of relying on the teachings of psychology, the sin is more easily pardoned. But this is not the only respect in which Ziller’s _Pedagogy_ is not up to the times. Ziller defined pedagogy as the influences, formed according to ethical points of view, which are brought to bear on the mind of the pupil, and would not admit influences brought to bear on the body, in so far as such should enter into the pedagogic system. This misconception also springs from Ziller’s adherence to the Herbartian school, which represents, as we well know, a metaphysical pluralism; but it is in a still higher degree due to the fact, that in Ziller’s day both the intimate relation between physiological and psychological processes had not been satisfactorily established, and also were not sufficiently known to him. If it were otherwise, his pluralism need by no means have necessarily led him into such one-sidedness, for this metaphysical pluralism does not exclude a monistic conception of _phenomena_; even assuming this doctrine, one may say that motion and feeling are two different but inseparable sides of the same phenomenon. The “real things” produce by their interaction, simultaneously and of necessity, both an inner side and an outer; for which reason one of our foremost psychologists, Volkmann of Volkmar, explicitly terms Herbart’s psychology monistic (_Text-book of Psychology_, second edition, I, 63). A psychologico-physiological work, from which the new editor of Ziller’s _Pedagogy_ might have extracted many valuable things, is the book of the Italian MOSSO, _On Fatigue_, which has just been translated into German,[52] and which will excite much attention owing to the present active discussion of the question of overwork. Supplementary to this work I will also mention a little tract by DR. BURGERSTEIN of Vienna, entitled _Die Arbeitskurve einer Schulstunde_.[53] This tract is a lecture, which the author gave at the Seventh International Congress for Hygiene and Demography at London, and in which he seeks to find by statistical methods, the duration of a “school-period”—a very laboriously composed treatise and one difficult to read, but possessed of high interest in psychological and pedagogic respects.