often accepted oppositional relation between red-green and yellow-blue owes its existence to aught inherent in the psychological analysis itself. Similar doubt besets other such conclusions. Considering, then, the uncertain charater of even the psychological inferences drawn from an analysis of the sensations, it is far more precarious to draw conclusions as to the physiological processes involved. The author's general attitude towards the whole question, aside from the specific case just referred to, is given in his introductory paper, already briefly mentioned, in connection with his discussion of the theory of specific comparisons. The point discussed is the validity of assuming, from the possibility of making comparisons of similarity between sensations unlike in quality (e.g. similarity in brightness of two different colors) the existence of identical psychological or physiological elements which determine such similarity. "If a physiological or a pyschological theory leads us to assume in all [light] sensations a definite element, which determines our impressions of brightness, then we may, on the basis of the theory, correctly refer to the equality or inequality of that element; but we may not, conversely, deduce from the possibility of a brightnesscomparison the existence of such an element" (p. 28). The insistence is, it is clear, so far as physiological inference is concerned, on the use of only those physiological concepts in explanation which result logically from a physiological theory based on recognized physiological procedure (e.g. the response of a sense organ to its adequate stimuli), and not on detached psychological analysis. The second point that I wished to bring forward,-v. KRIES'S estimate of the achievements of research in visual sensation, may be best stated in his own language: "If, in closing, we summarize how far theoretical concepts make it possible for us to elucidate and interpret the facts, and indicate, in general, the state of our problem, we may perhaps say, as of chief importance, that the view which we have characterized as 'Duplizitätstheorie' explains in a wholly satisfactory way a large number of functionally related phenomena This theory regards the rods, containing visual purple, as the organs of 'twilight vision,' and the cones as mediating a relatively different mode of vision, which we have called 'day vision.' One may further consider, in the light of a zone theory [Zonentheorie], the elements that mediate day vision as composed in their peripheral segments of red, green and violet components, on the relative degrees of activity of which the character of the sensations in part depends; in part, however, on other [more central] factors, which lead us to assume special conditions of color vision [Farbigkeit], to distinguish, namely, on one hand a red-green and on the other a yellow-blue sense. With these assumptions one may take account not, to be sure, of all, but nevertheless of a very great number of the known facts. We may, indeed, represent the protanopic [red-blind] and the deuteranopic [green-blind] visual organs as originating in a lack of the red and green components respectively, the 'rotanomale' and the 'grünanomale' in a variation in the nature of the red or the green component, and the color blindness of the eccentric regions of the retina, as well as acquired color blindness, in a lack of the more centrally conditioned red-green and yellow-blue senses; we are then in a position to represent simply the large number of facts that are found in the vision of these various individuals, or of the various parts of the visual organ, and to account for them, with simple presuppositions, in a way throughout and exactly (so far as we can say) in accord with experience." To exhaust the significance of this passage would require a synopsis of the whole article. The essence of the "Duplizitätstheorie" (for which it is hard to find a good translation) is, however, that the retina is a twofold visual apparatus, the rods, capable of "dark-adaptation," mediating colorless light in the presence of weak stimuli (twilight vision), and the cones, scarcely influenced by such adaptation, mediating our ordinary color (day) vision. This is perhaps the most widely accepted assumption in visual sensation, and to V. KRIES is due the chief credit of its experimental development. The zone theory assumes the validity of the triple-component theory (YOUNG-HELMHOLTZ) for peripherally situated visual elements, the possibility, however, in order to explain certain facts referred to in the quoted passage, of a fourfold division of elements, which form the basis of AUBERT'S and HERING'S thought, for the central [brain] portions of the visual apparatus. Since the article is in no sense a defence or a criticism of any exclusive theory, but rather a calm attempt to do justice, in both fact and theory, to the various and perplexing results of accomplished research, it would be inept, in this short review, to attempt to epitomize the arguments for or against the various theories. One feels, however, that the effect of v. KRIES's present contribution will be to win still more serious consideration for HELMHOLTZ'S general point of view, and to raise further questionings as to whether HERING's theory can so legitimately account for the manifold facts as is often assumed. One awaits therefore, with considerable interest, the appearance of HERINGS' pronounced volume for "GRAEFE-SAEMISCH'S Handbuch." It is a pleasure to read v. KRIES; for, while the style is often involved (at least for a foreigner) and occasionally abstract, the exposition is so objective, the discussion so subtle and free from polemic, the whole spirit so just, that one may well devote time and effort to master this latest and fullest review of visual sensation. R. P. ANGIER Meehan, Joseph. The Berlin "Thinking" Horse. Nature. 1904, 70, 602, 603. Cole, R. Langton. Thinking Cats. Nature, 1904 71, 31. Both of these articles were called forth by notes which had appeared in previous numbers of Nature. The first is in response to a note in Vol. 70, p. 510 (Sept. 22, 1904), stating that a committee which had examined the performances of a horse at Berlin, known as "Clever Hans," had decided that several remarkable things he was capable of doing were not "tricks," but "due to the mental powers of the animal." Mr. MEEHAN takes exception to this view on the ground that fully as wonderful performances of a horse named "Mahomet" he knows to have been tricks pure and simple, the horse being entirely dependent upon the prompting of his trainer. He cites also a similar case of a collie dog which could spell out words by selecting the proper letters of the alphabet, play a game of cards, etc., and explains that the trick was accomplished by slight and almost unnoticeable signals given by its trainer. Mr. MEEHAN mentions a cat which climbs a doorpost and opens the latch with her paw, and this he thinks "for a cat is more wonderful than are all the performances of the Berlin ‘thinking horse' for a steed." It is apparently this observation which called out a note by "Y. N." in Nature Vol. 71, p. 9 (Nov. 3, 1904) and that referred to by the second title given above, both of which relate anecdotes which are supposed to bear on the "thinking" powers of cats. LEON J. COLE van Rynberk, G. Tentativi di localizzazioni funzionali nel cervelletto. ivio di Fisiologia, Vol. I, pp. 569-574, 1904. Arch The investigator follows the anatomical scheme of BOLK (Grundlinien der vergleichenden Anatomie der Säugetiere, Monatschrift für Psychiatrie und Neurologie, Bd. XII, S. 432, 1902) and finds that a partial lesion of the lobulus simplex of the cerebellum in the dog causes unstable oscillations of the head. From this he concludes that the lobulus simplex is the control center for the muscles of the neck. J. C. B. Baglioni, Silvestro. Contributo alla fisiologia sperimentale dei movimenti riflessi; specificità qualitativa degli stimoli e specificità qualitativa dei riflessi. Archivio di Fisiologia, Vol. I, pp. 575-585, 1904. An interesting study of certain respiratory and other reflexes in the frog, in which it is shown that the reflex follows only from a specific quality of stimulation, and that this arrangement is biologically useful to the animal. J. C. B. Scaffidi, Vittorio. Sulla presenza di fibre efferenti nelle radici posteriorie e sulla origine delle fibre vasomotorie che si trovano in esse. Archivio di Fisiologia, Vol. I, pp. 586-603, 1904. A good review of the literature on the posterior roots and an account of seven experiments on dogs, from which it appears that no true Wallerian degeneration follows an incision, that the degeneration observed is traumatic, and that therefore we are not justified in assuming the presence of efferent fibers. Further researches are necessary to settle the question of the origin of the vasomotor fibers found there. J. C. B. Amer. Jour. Parker, G. H. The Reversal of Ciliary Movement in Metazoans. Physiol. 13, 1-16, 1905. The author has demonstrated that reversal of ciliary movement, few instances of which are known among the metazoa, occurs in the labial cilia of Metridium marginatum under certain conditions. Experiments indicate that reversal is due to the action of potassium ions, in case of the substances tested, and not to osmotic action or mechanical stimulation. Reversal occurs only where the stimulus is applied, and there is no evidence of a nervous reflex. R. M. Y. Pick. Des zones de Head et leur importance en psychiatrie. Journ. de psychol. norm. et pathol., 1, 113-117, 1904. An account of a case of interest particularly to psychologists in showing that abnormal sensations may give arise to the most diverse and peculiar interpretations. Some years ago HEAD pointed out that certain modifications of skin sensibility accompany derangements of internal organs (so called "zones of Head"). The case cited by PICK is that of a woman with hyperaesthesia in the region of the left breast, and with ideas of persecution, which, it was afterwards discovered, were due to the deranged sensations. The region of hyperaesthesia corresponded to that for the stomach, and further examination disclosed a dilatation of that organ. Under treatment, in a few days there was an amelioration of the stomach's condition and a disappearance of the delusions and sensory disturbances. 8. I. F. Wollenberg, R. Die Hypochondrie. Nothnagel's Specielle Pathologie und distinguishing between hypochondria and neurasthenia, and, in fact, hypochondria is not a disease entity, but only a psychopathic state, a morbid mental disposition of some kind. There are many varieties and fantastic aspects of the condition, but, in general, it may be said that the patient is usually depressed, and his attention directed chiefly to the condition of his body. WOLLENBERG rightly remarks that the cure comes 'not by means of physic, but by means of the physician. S. I. F. Hellpach, Willy. Grundlinien einer Psychologie der Hysterie. Leipzig, Englemann, 1904, viii. + 502. Price M.9. This is an exhaustively complete historical and analytical study of hysteria. Of its three chief parts the first deals with the problems of hysteria, the second, with the physiological and psychological phenomena included under this form of abnormal state or closely associated with it, the third, with the genesis of hysteria. As space does not permit of an attempt to indicate the views set forth in the book, a list of the titles of chapters will serve to suggest the general plan of treatment. 1. The development of the problems of hysteria. This is chiefly an historical sketch. 2. The concept of disease. A thoughtful discussion of the concept of reactive and productive abnormality, and of the conditions which determine their use. 3. The logic of psychopathology. In this interesting epistemological study of the subject, of chief value to the pathologist, is a discussion of disease as a developmental concept. 4. Suggestion and psychic causality An introduction to the author's analysis of hysteria. 5. The hysterical disturbances of movement. 6. The hysterical disturbances of perception. 7. 7. The hysterical intellect. 8. The psychophysical obstacle before the psychology of hysteria. 9. The sources of hysteria. This chapter contains an account of the relations of the child mind to hysteria, and also of the bearing of "docility" upon this form of psychic abnormality. IO. The path to hysteria. II. The development of the hysterical condition. 12. The socialpathological problem of hysteria. The work gives an excellent history of the special problems under consideration, and a convenient bibliography of important literature. It is of equal interest to the psychiatrist, the psychologist and the epistemologist; and one may venture the judgment that for all there is something of real value in the work. R. M. Y. Bressler, Joh. Wie beginnen Geisteskrankheiten? Marhold, Halle. pp. 56. 1905. Citing freely from such psychiatrists as KRAEPELIN, VON KRAFFT |