nervous system, while the spinal accessory fibers emerge from the cord, but it must be remembered that in the one case the fibers in question are afferent and in the other efferent in quality. In all its morphological and physiological characters, especially when studied from the comparative standpoint, the accessory is closely related to the vagus, and the view, so strongly supported by FÜRBRINGER, that the accessory is really a portion of the vagus, its nucleus being merely a downward extension of the vagus nucleus, seems to represent the true significance of the nerve. Whether or not the downward extension of the vagus nucleus be dependent upon the development of the trapezius and sterno-mastoid muscles, as the evidence presented by FÜRBRINGER seems to indicate, it is certain that comparative anatomy shows us a gradually increasing size of the vagus nucleus and its gradual extension into the spinal region. What the cause which determines the direction of the extension may be is at present unknown, but it is to be noted that the motor vagus nucleus is a lateral nucleus and its direct prolongation downward would therefore bring it into most intimate relation with the cell column from which the spinal white rami fibers take their origin. In its continued downward progress it may be supposed that it would gradually displace the majority of the cells of the sympathetic column throughout the spinal segments it traversed, forcing them to a lower level, so that throughout the region occupied by the extended nucleus, white rami fibers would be either wanting or few in number, while below the termination of the nucleus there would be a sudden increase in their number. This is exactly the condition which the results recorded above seem to show. There is one point, however, which such an explanation fails to clear up, namely, the existence of a second somewhat sudden increase in the number of white rami fibers in connection with the first and second thoracic nerves. The fact that this second outflow begins at about the level of the lowest nerve participating in the formation of the brachial plexus, and that it ceases at about the level of the beginning of the lumbo-sacral plexus, has suggested its dependence in some way upon the plexuses, a view which has been especially emphasized by HARMAN with reference to the upper limits of the outflow. The exact significance of the interdependence remains, however, obscure; but granting its existence, it still leaves room for the significance which has been assigned above to the upper outflow, and it would seem that there are two factors influencing the occurrence of white rami fibers in the cervical region, one of which is the development of the spinal accessory nerve, while the other is associated with the development of the brachial plexus. J. PLAYFAIR MCMURRICH. T. L. W. Bischoff. Literature. 1832. Nervi Accessorii Willisii Anatomia et Physiologia. Heidelbergae. 1832. Francois Franck. 1878. Sur l'innervation de l'iris. Marey's Travaux de Laboratoire, IV. M. Fürbringer. 1897. Ueber die spino-occipitalen Nerven der Selachier und Holocephalen und ihre vergleichende Morphologie. Gegenbaur's Festschrift, 1897. W. H. Gaskell. 1886. On the Structure, Distribution and Function of the Nerves which innervate the Visceral and Vascular Systems. Journ. of Physiol., VII, 1886. 1889. On the Relation between the Structure, Function, Distribution and origin of the Cranial Nerves, together with a Theory of the Origin of the nervous System of Vertebrates. Journ. of Physiol., X, 1889. N. B. Harman. 1900. The Anterior Limit of the Cervico-thoracic visceral efferent Nerves in Man. Journ. of Anat. and Physiol., XXXIV, 1900. J. N. Langley. 1892. On the Origin from the Spinal Cord of the Cervical and Upper Thoracic Sympathetic Fibers, with some Observations on white and gray Rami Communicantes. Philos. Trans. Roy. Soc., CLXXXIII., 1892. F. Nawrocki and J. Przybylski. 1891. Die pupillenerweiternden Nerven der Katze. Arch. f. Physiol., L, 1891. Both daily observation and numerous expressions in literature indicate the highly developed emotional life of birds. All other lower animals, even dogs, are inferior to them in this regard. Desiring to investigate this interesting subject, I undertook an experimental study of the respiratory reactions of the pigeon, an animal which is easily handled and which readily adapts itself to laboratory confinement. As a process through which to study mental phenomena, breathing combines two important advantages:-first, it is variable, being highly sensitive not only to changes of the blood, but also to impulses from the peripheral or from the central nervous system; and, secondly, its alterations may be easily recorded pneumographically. The value of the pneumograph 'The physiology of respiration is well summarized by STARLING in SCHAEFER'S Text-Book of Physiology, II, 274-312. ic method, especially in the study of feeling1 and attention,2 has long been recognized in human psychology, although the numerous difficulties involved in the interpretation of animal reactions have discouraged its use by comparative psychologists. In the experiments here to be reported an effort was made to obviate some of these difficulties by studying, for purposes of comparison, wholly different forms of reaction to the same stimuli. It is true that respiratory responses taken by themselves are of little value in the investigation of animal mind. But they assume a different aspect when correlated with directly comparable responses of a wholly different order. Thus, for example the influence of certain odors upon animal breathing would become material for psychology if we knew the free behavior of the animals in the presence of these same stimuli. Although the results of the present study are few and subject to correction3 it is hoped that they may lead to the use of this method in similar investigations. I wished to study the pigeon's respiratory movements by means of a pneumographic tracing secured under conditions as natural as possible. Hence a light, delicate apparatus was constructed to be worn by the animal when standing at its ease in the cote. The extreme difficulty of fastening the apparatus, however, made it necessary to test the bird in a kind of narrow nest, formed by cutting an oval opening in a fixed horizontal board (see Fig. 1, M.). The breast could thus be exposed below and its vertical, or sterno-vertebral, breathing movements secured by a tambour and recorded by the usual method.1 No attempt was made to register other kinds of breathing 'See the interesting study by ZONEFF and MEUMANN, Ueber die Begleiterscheinungen psychischer Vorgänge in Athem und Puls, Philosophische Studien, 18, 1-113, 1901. "See LEHMANN's paper, Ueber die Beziehung zwischen Athmung und Aufmerksamkeit, Philosophische Studien, 9, 66-95, 1894. A larger 3I refer especially to the relative percentages given in Table III. number of animals, tested under conditions more favorable, would give more reliable averages. 'LANGENDORFF, O. Physiologische Graphik. Leipzig und Wien, 1891. Paris, 1897. movements.1 The animal's feet were so troublesome that it was found to be best to secure them in an easy position by means of tape fastened to hooks behind. Great care was taken in placing the animal in the nest, and in adjusting the breast plate from day to day. If the tape were drawn too tightly, the breathing became abnormal; whereas, if drawn too loosely, the vertical position of the bird varied during the experiment and Fig. 1. Pneumograph. L, fixed board; M., position of animal; N, tambour, adjustment of breast-plate by means of screws, O and P; S, lower edge of box covering bird. altered the tension of the breast-plate, thus producing modifications in the tracing which were not due to the stimuli. No records were used which appeared untrustworthy. To avoid fright, the room was usually darkened before the bird was handled. In no case was it kept in position longer than was absolutely necessary. BERT P. Leçons sur la physiologie comparée de la respiration, 323-4. Paris, 1870. 2KLEIN, L. W. Methods in Animal Psychology, American Journal of Psychology, 10, 256-279, 1897. MILLS, W. Nature of Animal Intelligence and Methods of Investigating it, Psychological Review, 6, 262-274, 1897. |