One of his colleagues, Professor Kroman has proposed in his "Logik and Psychologie" a theory that is called by the same name. Yet Kroman's psycho-physical materialism, Dr. Lehmann declares, is widely different from his own; the former being "a mutual causal relation between the Physical and Psychical within the limits of the Atom," which, says Dr. Lehmann, "would make the explanation of complex psychical phenomena impossible."
The psycho-physical materialism of Dr. Lehmann, our author maintains, agrees in all essential points with the views of Professor Münsterberg (Freiburg in Baden).[65]
[65] The observations of Professor Münsterberg were reviewed in The Open Court No. 134.
The laboratory work done by Professor Münsterberg was published after Dr. Lehmann had finished his lectures. A certain similarity between Dr. Lehmann's views and those of the Freiburg Professor cannot be denied, yet it is more than doubtful whether Professor Münsterberg would recognise this similarity in the same measure as Dr. Lehmann does. The fact is that Dr. Lehmann has progressed in the direction which the German school of Wundt has taken; yet he has not as yet reached the same clearness; he is still entangled in Cartesian ideas, as is shown by his way of proposing problems: for instance in his treatment of the problem of will, which he justly calls "der eigentliche Probirstein der Hypothese," and of Attention, "the most enigmatic of all states of the soul" (der räthselhafteste aller Seelenzustände). In these and in other considerations Dr. Lehmann shows that he is still far from the positive standpoint by which Münsterberg's investigations are distinguished. It is very strange that in speaking of Attention M. Ribot's name has not even been alluded to. If the author had shown a familiarity with some of the monographs of this great French psychologist, he might have saved himself much work.
κρς.
DER HELIOTROPISMUS DER THIERE UND SEINE UEBEREINSTIMMUNG MIT DEM
HELIOTROPISMUS DER PFLANZEN. By Dr. J. Loeb. Würzburg: Verlag von
George Hertz.
The object of this work is to fill a gap in the treatment of the subject of animal movement depending on light, and to explain it by a consideration of the actual facts. After stating that the effect of light upon animal movement is purely mechanical, and that it is governed partly by the action of the light as the exciting cause, and partly by the structure of the sensitive organisation, Dr. Loeb proceeds, "I will now prove that the direction of the light rays determines quite generally the movements induced in animals by the light, no less than the direction of plant movement, and that the orientation not only of plants but of animals, depends upon the bodily form of the latter, in so far as the dorsiventral animals themselves move with the median plane in the direction of the light rays," etc. The more refrangible are the rays of light the more efficacious is its mechanical action upon animal and plant movement, which is affected also by the constant intensity of the light and its temperature. Thus it appears that the moth's flight into a flame must be considered as the same mechanical process as, for instance, the motions of sunflowers, the growth of the sprouting axis in buds, etc. Dr. Loeb's conclusion that the circumstances which govern the movements of animals towards the light are conformable to those which have been already recognised in relation to plant-movement, is supported by numerous facts, which appear to fully establish the accuracy of his observations and deductions.
The diligent author who is at present engaged in scientific investigations at the stazione zoologica in Naples, has in the mean time published a series of further observations on the same question, all of which, as was to be expected, corroborate the propositions set forth in the above mentioned little book. We have before us two reprints, one from the Biologische Centralblatt, Vol. X, Nos. 5 and 6, 1890, the other the Archiv f. d. ges. Phys., Vol. XLVII, with one plate and two wood-cuts, the former treating of the heliotropism of the nauplii of Balanus perforatus, whose periodical migrations are shown to depend upon the action of the light, the latter discussing the common features of heliotropism in animals and plants.
UNTERSUCHUNGEN ZUR PHYSIOLOGISCHEN MORPHOLOGIE DER THIERE. 1. UEBER
HETEROMORPHOSE. By Dr. Jacques Loeb. With 1 plate and 3 figures.
Würzburg: George Hertz.
Julius von Sachs, Vöchting, Noll, and other botanists have successfully opened the way to a knowledge of the growth of plants in their causal conditions. This method has been applied to the physiology of animals by Pflüger. The present pamphlet is a contribution to this endeavor by Dr. Loeb, whose special object has been to determine the laws of the restoration of lost organs in animal organisms. Botanists have found that if a plant that has undergone the loss of an organ has to build it up again, the new organ will be different from the original organ, and this difference can be determined by law. Dr. Loeb inquires whether the same can be said of the reconstruction of the lost organs of animals.