. Text-book of normal histology: including an account of the development of the tissues and of the organs. the complexity of their structure brought about by the presenceof the root-tracts of the optic nerve. In transverse section thesebodies present four layers, which, from the upper or dorsal surfacetowards the Sylvian canal, are— I. The stratum zonale, enveloping the superficial portions of 322 NORMAL HISTOLOGY. the bodies ; in man and apes this layer is unusually well developed,reaching a thickness of 30-40 ix ; the interlacing fibres, derivedfrom the optic tract, form a lamina rather than
. Text-book of normal histology: including an account of the development of the tissues and of the organs. the complexity of their structure brought about by the presenceof the root-tracts of the optic nerve. In transverse section thesebodies present four layers, which, from the upper or dorsal surfacetowards the Sylvian canal, are— I. The stratum zonale, enveloping the superficial portions of 322 NORMAL HISTOLOGY. the bodies ; in man and apes this layer is unusually well developed,reaching a thickness of 30-40 ix ; the interlacing fibres, derivedfrom the optic tract, form a lamina rather than distinctly-groupedbundles. 2. The stratum cinereum, a cap-like mass of gray matter, em-bracing the subjacent optic fibres, and containing numerous nerve-cells of varying size, the larger ones occupying the deeper parts ofthe layer. 3. The stratum opticum, consisting of the continuation of thepreceding gray matter, through which extend the bundles of opticnerve-fibres entering by the superior brachium ; posteriorly^the fibresare fine, while anteriorly they become robust to take part in the Fig. Section across superior corpora quadrigemina and adjacent part of thalamus : i,Sylvian aqueduct ; ^r, gray matter of aqueduct; , quadrigeminal body, con-sisting of, /, stratum lemnisci, o, stratum opticum, c, stratum cinereum ; Th, thala-mus (its pulvinar); , , internal and external geniculate bodies ; , ,superior and inferior brachia ; /, upper fillet; /./., posterior longitudinal bundle ; r,raphe; ///, third nerve ; «.///, its nucleus ; /././., posterior perforated space ; ,substantia nigra, above this tegmentum with circular nucleus ; cr, crusta ; //, optictract; M, medulla of hemisphere; , nucleus caudatus ; si, stria terminalis.(After Quain-Meynert.) constitution of the optic tract. Among the profusely distributednerve-cells are elements of considerable size whose axis-cylinderprocesses extend largely within the underlying zone. 4. The st
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Keywords: ., bookcentury1800, bookdecade1890, bookpublisherphiladelphiajblipp
