the epistriatum in teleosts is a prophesy of the evolution of the cortex cerebri in the later phylogeny. The olfactory and gustatory tertiary tracts end together throughout the inferior lobe and they have a common descending conduction path, the tractus lobo-bulbaris. In addition to this ventral olfactory path, there is the dorsal tertiary tract from the fore-brain to the habenula and its descending path of the fourth order, MEYNERT'S fasciculus retroflexus. This path offers opportunity for somatic sensory (including optic) and somatic motor connections analogous to those provided for the sense of taste in the inferior secondary nucleus.

If the olfacto-gustatory connections of the human body are at all similar to these of fishes, this relation offers a possible anatomical correlate of the familiar fact of experience that subjectively we distriminate tastes and smells only imperfectly, in many cases not at all, without the aid of collateral physiological experimentation to determine which organ receives the stimulus.

It is freely granted that these comparisons are, in the present state of our knowledge, rather fanciful. They are offered merely as the first practicable working hypothesis for a correlation of the olfactory with the other sensory mechanisms. If the anterior end of the primary nerve tube lies in the region of the preoptic recess, as seems to be now commonly assumed, the peculiar relations of the rhinencephalon are to be explained as due to the suppression of the most anterior sensory and motor centers of other systems, leaving the olfactory apparatus free to develop without constraint.

The most striking difference noticeable in the diagram between the centers for taste and smell is the apparently ventral position of the primary and secondary olfactory centers as contrasted with the dorsal centers for taste. But if the anterior end of the brain tube lies near the preoptic recess in the lamina terminalis, this difficulty disappears; for all structures in front of this point must have been developed from the dorsal wall of the brain tube. That is, the secondary fore-brain, including the entire rhinencephalon, is a dorsal structure.

Our conclusion, then, is that the morphological relations

expressed in Fig. 40 strongly suggest that the central reflex mechanisms of taste and smell have had a common phylogenetic origin and that they have been from the first quite independent of the so-called somatic sensory centers.

LITERATURE CITED.

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'96. Beitrag zum Studium der Medulla oblongata, des Kleinhirns und des Ursprungs der Gehirnnerven. Trans. by Bresler. Leipzig.

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David, J. J.

'92. Die Lobi inferiores des Teleostier und Ganoidengehirns. (Dissertation.) Basel.

Edinger, L

'96. Vorlesungen über den Bau der Nervösen Centralorgane des Menschen und der Thiere. 5 Edition. Leipzig.

'03. Bericht über die Leistungen auf dem Gebiete der Anatomie des Centralnervensystem. 1901-1902. Reprinted from Schmidt's Jahrbücher, vol. 279.

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Forel, A.

'91. Ueber das Verhältniss der experimentellen Atrophie und Degenerationsmethode zur Anatomie und Histologie des Centralnervensystems. Ursprung des IX, X und XII Hirnnerven. Festschr. f. Nägeli und Kölliker, Zurich.

Fritsch, G.

'78. Untersuchungen über den feineren Bau des Fischgehirns. Berlin. van Gehuchten, A.

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Goronowitsch, N.

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Herrick, C. L.

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LITERARY NOTICES.

Harris, Wilfred. Binocular and Stereoscopic Vision in Man and Other Vertebrates, with its Relation to the Decussation of the Optic Nerves, the Ocular Movements, and the Pupil Light Reflex. Brain, 1904, 27. 107-147. 'Stereoscopic' vision differs from 'binocular' in that in the former the images of a given object fall simultaneously on homonymous sides of the two retinae, while in the latter they may fall either homonymously or heteronymously. Now from examining experimentally the optic chiasm in the toad, chameleon, pigeon, owl, and rabbit, and from the reports of others on the cat, mouse and rat, the author concludes (p. 107) that "The decussation of the optic nerves at the chiasma is complete in all fishes, amphibia, reptiles and birds, whether possessed of binocular vision or not ;" and this notwithstanding that (p. 111) “In the lowest fishes, the cyclostoma, the optic nerves do not cross the middle line, but each arises from the corresponding side of the forebrain, the nerves passing to the eyes without decussation." At most, the author may be said to have shown that 'binocular' (but not stereoscopic) vision is not incompatible with total decussation at the chiasm. He thinks probable that "the association of the visual impression received by the two eyes of the same object is effected by the commissural fibres of the corpus callosum." True stereoscopic vision is supposed impossible unless the decussation is only partial, that is, unless the optic fibres from homonymous sides of the retinae lead to the same cortical centres.

The macula lutea is probably not represented in both halves of the brain as has sometimes been concluded from the fact that in most cases of permanent hemianopia, the dividing line between the blind. and the seeing halves of the field is found to pass around the fixation point, leaving it included in the seeing half of the field for each eye. But this fact is probably due to a greater power of resisting disease possessed by the macular fibres, since in cases of transient hemianopia the dividing line between the seeing and the blind fields passes exactly through the fixation point, and when recovery sets in it begins at the macular region. The macular fibres do not bifurcate at the chiasm.

Conjugate, lateral and vertical movements of the two eyes (but not movements of convergence) are directly associated with semidecussation of the optic nerves at the chiasm. The more complete

the decussation, the more independently of each other the eyes will be apt to move.

As to the pupillary reflex, Dr. HARRIS finds (p. 139) that “in all those animals in which there is a total decussation of the optic nerves at the chiasma, only that pupil contracts which is exposed to light." In such animals the course of the reflex is probably from the eye along the optic nerve and tract to the anterior corpus quadrigeminum of the opposite side, thence by MEYNERT'S fountain decussation to the nucleus of the third nerve on the former side, and thence back by the third nerve to the iris of the eye stimulated. In man and higher animals where the pupillary reflex to stimulation of one eye is binocular (consensual), the anterior corpus quadrigeminum of either side must be connected with the third nerve nuclei on both sides.

E. B. H.

Le Bon, Gustave. Psychologie de l'Education. Paris, Flammarion, 1904. (5. éd.) pp. 304.

LE BON's discussion of the psychological bases of teaching is of interest to comparative psychologists, for he maintains that instincts. develop from conscious acts From this point of view all developmental progress in the race, as in the individual, is conditioned by the mechanizing of conscious activities. Education itself should be, in LE BON's opinion, the facilitation of this process. "L'éducation est l'art de faire passer le conscient dans l'inconscient."

LE BON's treatment of the psychology of instruction and education makes clear the significance of studies in the development of activity, and suggests to the comparative psychologist certain lines of investigation which may yield results of practical importance in education.

R. M. Y.

E. Bolnet. Les Doctrines Médicales, Leur Evolution. Bibliothèque de Philosophie scientifique, Flammarion, Editeur, Paris, 1905.

A brief account of medical doctrines from the time antedating HIPPOCRATES, through the Middle Ages, to PASTEUR. The modern theories of immunity and of infection, with their applications to therapy and hygiene, are discussed.

J. Hericonot.

W. B. C.

Les Frontièrs de la Maladie. Bibliothèque de Philosophie Scientifique, Flammarion, Editeur, Paris, 1905.

An interesting and important discussion of the borderland between health and disease. The insideous beginnings of disturbances of nutrition and metabolism, of auto-intoxication, of chronic infectious diseases, and of attenuated forms of acute infections are treated in an illuminating manner.

W. B. C.