. The American journal of anatomy. ints has been published by Weigner, 05, who studied serialsections of rodent and human material, and found it possible to traceto their destination the fibers of the n. intermedins by their histologicalcharacter; that is to say, from the frequency of the sheath nuclei, thesmall size of the fibers, and the presence of scattered ganglion cells lyingalong the course of the fibers. The common identity of the pars intermedins geniculate ganglion andchorda tympani, as described by Sapolini and Penso, in the adult is lesseasily seen in the early embryo owing to the
. The American journal of anatomy. ints has been published by Weigner, 05, who studied serialsections of rodent and human material, and found it possible to traceto their destination the fibers of the n. intermedins by their histologicalcharacter; that is to say, from the frequency of the sheath nuclei, thesmall size of the fibers, and the presence of scattered ganglion cells lyingalong the course of the fibers. The common identity of the pars intermedins geniculate ganglion andchorda tympani, as described by Sapolini and Penso, in the adult is lesseasily seen in the early embryo owing to the incomplete differentiationof these structures. In fact. His, Jr., 89, states that up to the thirdmonth no nerve is to be seen arising between facial and acoustic, andhe concludes that the intermedins must until that time run in thetrunks of these two nerves. In our embryos, however, it was foundearlier than that. The Fig. 6 represents the pars intermedins and geni-culate ganglion in an embryo of 3^ weeks, and they can also be dis-. FiG. 8. Sagittal section through the geniculate ganglion and facial nerveof a 30 mm. human embryo, No. 75, Mall Collection, showing how they areseparated by a connective tissue partition. tinguished in embryo ISTo. 148, Mall collection, which is about 20 daysold. The ganglion can be made out first, and shortly after that thepath of loose fibers connecting it with the neural tube. As is seen inFig. 6, the ganglion and its proximal root are at this early period dis-tinctly separate from the acoustic mass, and it is only as the acousticmass increases in size that it could be said to fuse with the geniculateganglion; the existence even here of a real fusion is doubted, for noappearance was observed in any of our embryos that could not be ex-plained by mere contiguity. The separation existing between theseganglia, in the early stages, merits the attention of those who would George L. Streeter 163 believe that they have a common origin, as was thought by t
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectanatomy, bookyear1901
