172 



A STUDY OF THE SUPERIOR OLIVE. 



flowing around the periphery of the nucleus and in the interval between the medial 

 and lateral masses, filling in the hila and forming dense whorls around the superior 

 pole, making altogether a much richer network than is found in any other form. 



In man there is a well-developed fiber complex, both intranuclear and extra- 

 nuclear; the latter, in particular, shows a tendency to group into bundles. These 

 can be seen at places cutting the substance of the nuclear mass in the same manner, 

 though in much less degree, than is commonly found in the inferior olive. 



BIBLIOGRAPHY. 



BAGINSKY, B., 1890. Ueber den Ursprung und den cen- 

 tralen Verlauf dcr Nervus acusticus des Kanin- 

 chens und dcr Katze. Arch. f. path. Anat., vol. 

 119, p. 81-92. 



BARKER, L. F., 1899. The nervous system and its con- 

 stituent neurones. 



BRUCE, A., 1892. Illustrations of the nerve tracts in the 

 mid- and hind-brain, and the cranial nerves 

 arising therefrom. 



CAJAL, RAMON T, 1896. Beitrag zum Studium der 

 Medulla oblongata, etc. 



FERRIER, D., 1890. Croonian lectures on cerebral locali- 

 zation. Delivered before the Royal College of 

 Physicians, London; vol. 6. 



FLEICHSIG, P., 1886. Zur Lehrc vom centralen Verlauf 

 der Sinnesnerven. Neurol. Centralbl., Bd. 5, 

 p. 97-100. 



, 1890. Weitere Mittheilungen ueber die Bezie- 

 hungen des unteren Vierhtigels zum Hornerven. 

 Neurol. Centralb., Bd. 9, p. 98-100. 



v. KOLLIKER, A., 1896. Handbuch der Gewebelehre. 



v. MONAKOW, C., 1890. Strise acusticse und untere 

 Schleife. Arch. f. Psychiat., Bd. 22, p. 1-26. 



SANTEE, H. E., 1915. Anatomy of the brain and spinal 

 cord. 



WEED, L. H., 1914. A reconstruction of the nuclear 

 masses in the lower portion of the human brain- 

 stem. Carnegie Inst. Wash., Pub. No. 191. 



DESCRIPTION OF PLATES. 



PLATE 1. 



FIG. 2. Photograph of the ventral aspect of three models of the superior olive: A, adult cat; B, dog fetus; C, human 

 fetus. A and B are oriented to conform to their natural position in the stem. C has been placed to show the 

 relations of its different parts to each other; the picture accordingly shows the ventro-lateral view of the 

 vertically placed nucleus, whereas in its proper position it should lean sharply to the right with some twisting 

 upon its long axis. In A and B the S-shaped lateral mass can be clearly seen, separate from the medial bar 

 in A (cat nucleus) but continuous with it in the lower part for a short distance ventrally in B. 



FIG. 3. Dorsal view of the same models. In A the interval between the two masses is well shown. In B the marked 

 irregularity of the lateral bar of the S a <id the absence of continuity of the two masses are noted. In C the 

 three component portions are clearly shown, though the interval between the medial and lateral masses is 

 slight. 



FIG. 4. High power microphotograph of the superior olive in an adult cat, showing the characteristic spindle-cells. 

 All of the sections in figures 4-6 were cut 20 microns and are too thick to give sharp pictures. 



FIG. 5. Spindle-cell in the adult dog. 



FIG. 6. High-power photograph of the human superior olive in embryo No. 28, in which the closely packed arrange- 

 ment and large number of spindle-cells are evident. In all of these the same character of cell (the typical 

 spindle) will be found. 



PLATE 2. 



FIG. 7. Lower power microphotograph of a section of the pons of an adult cat. Here the superior olive can be seen 

 to consist of a bar-shaped medial portion and an S-shaped lateral portion, together forming a compact mass 

 lying on the dorsal surface of the trapezoid body between the emergent fibers of the adbueent and facial 

 nerves. 



FIG. 8. Microphotograph of the superior olivary region in a 115 mm. dog fetus. The olive consists of a racquet- 

 shaped medial portion and an S-shaped lateral portion. The cluster of large cells dorsal to the latter is the 

 nucleus of origin of the facial nerve. 



F IG g_ Microphotograph of a Yamagiwa preparation of the brain-stem of an adult dog, showing the Q-shaped medial 

 portion of the superior olive with the emergent fibers of the abducent nerve passing through it. The lateral 

 portion is Q-shaped. 



FIG. 10. Photograph of a Pal-Weigert preparation in the region of the superior olive in a new-born infant, showing 

 the fiber elements. To the right of the section is the thick strand of fibers of the facial nerve, and jui-t 

 medial to this is its nucleus of origin with fibers streaming upward toward the genu. Between the facial and 

 abducent nerves is the superior olive, lying medial and ventral to the nucleus of the facial. The fine fibers 

 streaming dorsally from it constitute the olivary peduncle. 



