338 



OF THE PRIMARY TISSUES OF THE HUMAN BODY. 



with those of smallest diameter. They may be traced into the ganglia of the 

 Sympathetic, into the ganglia on the posterior roots of the Spinal nerves, and 

 even to the ganglionic matter of the Brain and Spinal Cord. 1 



340. The second primary element of the Nervous system, without which the 

 fibrous portion would seem to be totally inoperative, is composed of nucleated 

 Cells or Vesicles, containing a finely granular substance, and lying somewhat 

 loosely in the midst of a minute plexus of bloodvessels. Their original form 

 may be regarded as globular ; whence they have been called ganglion-globules. 

 This, however, is liable to alteration ; sometimes, perhaps, from external com- 

 pression } but more commonly through their own irregular mode of growth. 

 They frequently extend themselves into long processes, which may give them 

 (according to the number thus projecting) a " caudate" or a " stellate" form 

 (Fig. 107). These processes are composed of a finely-granular substance, re- 

 Fig. 107. 



Various forms of Ganglionic Vesicles : A, B, large stellate cells, with their prolongations, from the anterior 

 horn of the gray matter of the spinal cord; c, nerve-cell with its connected fibre, from the anastomosis of the 

 facial and auditory nerves in the Meatus auditorius internus of the Ox : a, cell-wall ; b, cell-contents ; c, pig- 

 ment ; d, nucleus ; e, prolongation forming the sheath of the fibre ; /, nerve-fibre : D, nerve-cell from the sub- 

 stantia ferruginea of Man : E, smaller cell from the Spinal Cord. Magnified 350 diameters. 



sembling that of the interior of the vesicle, with which they seem to be dis- 

 tinctly continuous. They are very liable to break off near the vesicle; but if 

 traced to a distance, they are found to divide and subdivide, and at last to 

 give off some extremely fine transparent fibres ; some of which seem to inosculate 

 with those of other stellate cells, whilst others become continuous with the axis- 



* Much controversy has taken place in Germany, regarding the existence of a set of 

 fibres peculiar to the Sympathetic system. The gray or gelatinous fibres, described by 

 Remak, and (following him) by Miiller and others, as essentially constituting the " organic" 

 system of Nerves, have been affirmed by several eminent authorities not to be entitled to 

 the designation of nerve-fibres at all, but to be a form of simple fibrous tissue ; and the 

 fine tubular fibres, described above, were considered by Bidder and Volkmann to be the 

 peculiar constituents of the Sympathetic system. Further researches, however, seem to 

 have removed all doubt as to the veal nature of the gelatinous fibres; as their continuity 

 with the stellate prolongations of the ganglionic cells, and with the tubular fibres, is now 

 established by the concurrent testimony of many excellent observers. For a valuable 

 summary of this controversy, see Dr. Sharpey's Introduction to " Quain's Elements of 

 Anatomy," vol. ii. p. 177, Am. Ed. 



