on several of the author's degenerative experiments on rabbits. The Marchi method was supplemented with the methods of indirect Wallerian degeneration and of NISSL. The vestibulo-spinal tract arises exclusively after DEITER'S nucleus and descends in the anterior column as far as the lumbo-sacral region. The spinal portion of the posterior longitudinal fasciculus is exclusively descending. Ascending fibers are found in this tract only within the bulb and mesencephalon. Both ascending and descending heterolateral fibers probably come as inferior arcuate fibers either from the terminal vestibular nucleus or from the tuberculum acusticum. The ascending homolateral fibers arise higher up, probably from the nucleus of BECHTEREW. The striae medullares arise exclusively in the tuberculum acusticum. G. E. C. Soukhanoff. Contribution à l'étude du réseau endocellulaire dans les éléments nerveux des ganglions spinaux. Le Névraxe, 1904, 6, 75-80. 'The endocellular net as observed by the KOPSCH Osmic acid method is identical with the GOLGI endocellular net, and is not the same structure as the canaliculi of HOLMGREN and others. G. E. C. Agababow, A. Ueber die Nerven der Sclera. Archiv f. mık. Anat., Bd. 63, H. 4, pp. 701-709, 1904. Hyde, Ida H. Localization of the Respiratory Center in the Skate. Amer. Jour. Physiol., 1904, 10, 236-258. By the employment of careful and precise methods of experimentation on living skates, Miss HYDE has demonstrated the segmental arrangement of the respiratory center. The animal under observation was placed on a board, and sea-water was passed in a continuous stream through a tube into the mouth. Artificial respiration could in this way be maintained for days. In a skate thus situated the medulla may be separated from the spinal cord and from those portions of the brain lying anterior to it without destroying its function as a respiratory center. Medisection of the medulla is followed, after the inhibitory effects of shock have passed off, by a resumption of coördinated respiratory movements on both sides of the body. The gill arches of one side may move in a rhythm quite different from that of the opposite The spiracles may keep time with the gill arches of their respective sides, or both spiracles may be in rhythm with the arches of one side. From the results of median section of the medulla it became evident that "the centers for the nervous respiratory mechanism in the skate were bilateral, each half controlling the movements of its respective side." Evidence of the segmental character of these bilateral respiratory centers was obtained by following medisection with hemisection. One lateral half of the medulla was separated into anterior and posterior divisions by a transverse cut. The arches and spiracle of the uninjured side continued their normal movements. The spiracle and first gill arch, controlled by the anterior division of the opposite side, sometimes exhibited a rhythm which differed both from the rhythm of the uninjured side and also from that of the remaining gill arches of the same side, which were under the control of the posterior division of the lateral half of the medulla. At times the respiratory mechanisms connected with all three divisions of the medulla moved in unison. Lesions of the different lobes of the medulla indicated that the ganglion cells of sensory respiratory neurones, those of the seventh, ninth and tenth cranial nerves, are situated in the lobus vagi. Motor ganglion cells and neuraxones were found ventrad of the lobus vagi and in the fasciculus longitudinalis posterior. F. W. C. Gardella, Eloisa. Azione dell' acido fenico sulla sensibilità gustativa. Archivio di Fisiologia, 1904, 1, 398-402. From its general anaesthetic properties we would expect phenic acid to cause a rise in the threshold of sensibility to taste stimuli. On the contrary, increasing strengths of phenic acid solution up to 3%, applied for 10 seconds, cause a lowering of the threshold for all four of the tastes, bitter, sweet, salt and acid, most of all for bitter. With a constant 2.5% solution and with varying time the threshold falls rapidly during the first 10 seconds, then rises to the normal at 30 seconds, and from there continues to ascend more slowly to 45 seconds. J. C. BELL. Langley, J. N. On the Effects of Union of the Central Part of the Cervical Sympathetic with the Peripheral Part of the Chorda tympani. Archivio di Fisiologia, 1904, 1, 505-511. Three cats were operated upon and in 89, 96 and 176 days respectively they were killed and the nerves examined. Experiments upon the operated cats and examination of the nerves led to the conclusion that "the sympathetic fibers had united with the nerve cells on the course of the chorda tympani, and in consequence that sympathetic preganglionic fibers are capable of uniting with other similar cells. . . which occur on the course of the cranial nerves." The observations also showed that "the formation of medullated fibers in a peripheral nerve may be caused by fibers reaching it which are themselves non-medullated." J. C. BELL. Carlson, A. J. The Rhythm Produced in the Resting Heart of Molluscs by the Stimulation of the Cardio-Accelerator Nerves. Amer. Jour. of Physiol., 1904, 12, 55-66. The author has proved that the cardio-accelerator nerves of molluscs when stimulated electrically produce rhythmical contractions of the resting heart. He is inclined to believe, also, that under favorable conditions the resting mammalian heart may likewise be caused to contract by stimulation of the accelerator nerves. The physiology of the cardiac nerves of invertebrates is of special interest because in some forms accelerator nerves alone are present, in others inhibitory nerves alone, and in others nerves which are both inhibitory and acceleratory. R. M. Y. Carlson, A. J. The Nervous Origin of the Heart-beat in Limulus, and the Nervous Nature of Co-ordination or Conduction in the Heart. Amer. Jour. of Physiol., 1904, 12, 67-74. "It can now be stated as a fact that in Limulus the origin of the heart-beat is nervous, not muscular, and that conduction of the impulse or the co-ordination of the different parts of the heart takes place through the nerves, not through the muscular tissue." This important conclusion Dr. CARLSON draws from the results of a series of ideally definite and well chosen experiments. He has shown (1) that lesion of the median and the two lateral nerves which supply the heart destroys coordination, (2) that cross-section of the heart does not interfere with co-ordinated rhythm so long as the nerves are intact, (3) that heartbeat ceases when the median nerve is severed. The author has found material which is particularly favorable for the study of heart action in its relation to the nervous system, and the importance of his work will be recognized at once by all who have interest in physiology. R. M. Y. Schiller, V. Ueber die physiologischen Wirkungen des Delphinins (Hegl). Arch. f. (Anat. u.) Physiol., 1904, 248-255, Taf. VI. Delphinin paralyzes the vagus endings in the heart to a marked R. P. degree. loteyko, J. Mécanisme physiologique de la réaction de dégénérescence des muscles. Travaux du Laboratoire de Physiologie, Instituts Solvay, 1904, 6, 59-78. The reaction of the muscle which has undergone degeneration because of separation from its nerve argues for contractility of the sarcoplasm, and a qualitative difference in irritability of the sarcoplasm as compared with the fibrillae. The author questions whether there may not be a similar qualitative differentiation of irritability in the substance of the nerve. G. E. C. Klein, Fr. Das Wesen des Reizes. Ein Beitrag zur Physiologie der Sinnesorgane, inbesondere des Auges. Arch. f. (Anat. u.) Physiol., 1904, 305-342. A fundamental attribute of protoplasm is that it is stimulated only by changes in the normal or usual external condition. The same thing applies to the nerve endings of the retina, hence certain conditions. are possible under which we are blind ("rest blindness"). Two such conditions inducing "rest blindness" have been investigated. These are (a) hindering as much as possible every eye movement, (b) illuminating the eye from an equally lighted ("reizlose") surface. The author thinks it probable that only an increase in the intensity of light can act as a stimulus, never decrease. R. P. Rothmann, M. Ueber die Leitungsbahnen des Berühungsreflexes unter Berücksichtigung der Hautreflexe des Menschen. Arch. f. (Anat. u.) Physiol., 1904, 256-270. In dogs and cats the conduction in either ascending or descending direction of the impulses in MUNK'S "contact" reflexes of the extremities, is not confined to a single sensory or motor fiber tract. The ascending impulses of the reflex are conducted in two fiber tracts: one in the anterior and one in the posterior column. There are also two paths for the descending impulses: the pyramidal tracts and MONAKOW's bundle. The "contact" reflex of lower animals agrees in many points with the skin reflex in man. R. P. Birukoff, B. Zur Theorie der Galvanotaxis. Arch. f. (Anat. u.) Physiol., 1904, 271-296. Galvanotaxis a combination of two factors: a physiological (general irritability) on the one hand, and a purely physical (kataphoric action on the other. R. P. Muskens, L. J. J. Studies on the Maintenance of the Equilibrium of Motion and its Disturbances, so-called "Forced Movements." Jour. of Physiol., 1904, 31, 204-221. Experiments producing forced movements after lesions of the central nervous system were performed on octopods, selachians (Acanthias, Scyllium), frogs, cats and rabbits. The conclusions with reference to lower vertebrates are: 1. That rolling after unilateral lesion of the hind-brain, and circus movement after unilateral lesion of the base of the mid-brain appear to be, in lower vertebrates, fundamental phenomena, especially localized in these parts; 2. That rolling to the impaired side and circus movement to the non-impaired side are phenomena narrowly related; 3. There is no reason to believe in any diametrical opposition of forced movements of an irritating and of a paralyzing nature. In cats and rabbits unilateral lesions of the middle and upper cerebellar peduncle and unilateral (partial more than com plete) removal of a lateral lobe of the cerebellum cause rolling movements to the side of the lesion, or a tendency to it. The most marked rolling was observed after lesion or section of the middle peduncle. Studies on the changes in the mobility of the eyeballs were also conducted. R. P. Woodworth, R. S. and Sherrington, C. S. A Pseudaffective Reflex and its Spinal Path. Jour. of Physiol., 1904, 31, 234-243. The lateral column furnishes the headward path in the spinal cord for nociceptive (algesic) arcs; each lateral column conveys such impulses from both lateral halves of the body, and somewhat preponderantly those from the crossed half; these relations are true whether the arcs be traced from skin, muscle or viscus. R. P. Langley, J. N. On the Question of Commissural Fibers between Nerve Cells having the Same Function and situated in the same Sympathetic Ganglion, and on the Function of Post-Ganglionic Nerve Plexuses. Jour. of Physiol., 1904, 31, 244-259. Concludes that since pilo-motor nerve-cells, in a given ganglion of the sympathetic system can be shown not to be connected with each other by commissural fibers, and that the same is true of pupillo-dilator and vaso-motor nerve-cells, it is fair to assume "that none of the nerve-cells of the sympathetic system, and none of the similar nervecells on the course of the cranial and sacral nerves are so connected." R. P. Langley, J. N. and Anderson, H. K. The Union of Different Kinds of Nerve Fibers. Jour. of Physiol., 1904, 31, 365-391. The nerve fibers dealt with are divisible into four classes, (a) the efferent fibers which run from the central nervous system and end in multi-nuclear striated muscle cells (efferent somatic fibers), (b) the efferent fibers which run from the central nervous system and end in ganglion cells (pre-ganglionic fibers), (c) the efferent fibers given off by the peripheral ganglia (post-ganglionic fibers) and (d) afferent fibers connected with nerve cells in the posterior root ganglia. The general conclusions drawn from the experiments are, (1) The central end of an efferent fiber can make functional connection with the peripheral end of any other efferent fiber of the same class whatever be the normal action produced by the two fibers. (2) The central end of any fiber of class (a) can make functional union with the peripheral end of any fiber of class (b), and the central end of any fiber of class (b) can make functional connection with the peripheral end of any fiber in class (a). (3) The peripheral ends of cut nerve fibers appear to have a chemotactic influence on the central ends. The chemotactic action is strong |