136 NERVOUS TISSUE. 



the crushing and breaking down of such fibres in the process of examina- 

 tion. In the ganglia properly so called, the cells are ]3acked up among 

 nerve-fibres, but each cell is also immediately surrounded by an 

 hiclosing capsule (fig, 93 I). 



The proper nervous substance of the brain and spinal cord is described 

 by Kulliker as being traversed in all directions and supported by a frame- 

 work of connective tissue — the '* retiform " con- 

 Fig- 92. nective tissue described at page 69. This is stated 

 to be formed of an interunion of ramified con- 

 nective tissue coi-puscles, or of a network of fine 

 fibres alone, originally proceeding from such cor- 

 puscles. Kolliker names this supporting struc- 

 ture the reticulum of the nervous centres (fig. 

 92). Virchow proposes the term neuroglia. 

 ' If'X^^^ ^^ "^^ ^*-'^ merely an open mesh-work, but consists 

 \n\ " also of fine laminae formed of a close interlace- 

 ment of the finest fibrils, disposed as mem- 

 Fig. 92. — Part op the branous partitions and tubular compartments 

 Reticuluji from the for separating and enclosing the nervous 

 Spinal Cord. bundles. Besides these ramified cells others are 

 Open meshes are seen found (Deitcrs) which are flattened and dis- 

 generaiiy but at two tj^ctlv fibrillatcd, somewhat like the cells of 



places close lamelljform ji"- ,• ,• t.^ ,i 



interlacements are shown, developing connective tissue. Moreover, the 

 Magnified 350 diameters granular matrix above described, in which the 

 (Kolliker). neiTC-cells are imbedded, is considered by Boll 



to be derived from connective tissue cells, which 

 have undergone a granular rather than a fibrillar metamorphosis.* 



Such being the structural elements of the nervous substance, we 

 have next to consider the arrangement of the cells and fibres in the 

 ganglia and nerves which they contribute to form ; the intimate 

 structure of the encephalon and spinal cord being treated of in the part 

 of this work which is devoted to special or descriptive anatomy. 



OF THE GANGLIA. 



The bodies so named are found in the following situations — viz. : 

 1. On the posterior root of each of the spinal nerves ; on one, and pro- 

 bably the corresponding root of the fifth nerve of the encephalon ; 

 and on the seventh pair, glosso-pharyngeal and pneumogastric nerves, 

 involving a greater or less amouu-t of their fibres ; also on the branches 

 of certain cerebro-spinal nerves. 2. Belonging to the sympathetic 

 nerve, (a) — In a series along each side of the vertebral column, con- 

 nected by nervous cords, and constituting what was once considered as 

 the trunk of the sympathetic, {h) — On "branches of the sympathetic ; 

 occurring numerously in the abdomen, thorax, neck, and "head ; gene- 

 rally in the midst of plexuses, or at the point of union of two or more 

 branches. Those which are found in several of the fosste of the cranium 

 and face are for the most part placed at the junction of fine branches of 

 the sympatlietic with branches, usually larger, of the cerebro-spinal 



* Stieda, Studiea iiber das centralc Nerven-systcm, Z. fur Zool., 1S6S, 1870. Golgi, 

 Contribuzione alle fina Anatoniia degli Organi ccntrali del Sistema ncrvoso ; Rivista 

 Clinica, 1871. Boll, Die Ilistologie und Histiogenese der Nerviise Ceutral-organe, 

 Berlin, 1873. 



