NEBYOUS SYSTEM: AXD GENERAL SENSATION. 



37 



This cellular tissue, with its nucleated fibres, has been errone- 

 ously described as a third and distinct special element of the 

 nervous system, under the name of the organic fibrils, proba- 

 bly from their abundance in the sympathetic and its ganglia, 

 or of the nodulated fibrils fibrillae nodulosae. 



The ganglionic corpuscles present numerous varieties in re- 

 gard to form, size, arrangement, and the structure of their re- 

 moter elements. They are singularly delicate and destructible 

 in the central masses. Here the cellular sheath, just de- 

 scribed, is entirely wanting ; and the finely granular substance 

 of which they consist, and the clear nucleus which they con- 

 tain, are so diffluent, that it is seldom we succeed in finding 

 more under our microscopes than a homogeneous, finely granu- 

 lar mass. Whether from the great nervous centres^ or from 

 the more peripheral ganglia, they are generally either round 

 or oval in figure (figs. 14, 16*, 17, a, and 18, a) ; frequently, 

 however, they 

 are elongated, 

 sausage shaped, 

 four - cornered, 

 tetrahedral, and 

 furnished with 

 off-sets or pro- 

 cesses (fig. 18, 

 B) ; it is seldom 

 that two are seen 

 connected by a 

 bridge. The nu- 

 cleus is always 

 clear, roundish, 

 or lengthened 

 and simple; the 

 nucleolus is ex- 

 tremely small. 

 In their gene- 

 ral external ap- 

 pearance, these 

 ganglionic cor- 

 puscles have a 

 surprising re- 

 semblance to 



Fig. 18. Primary fibres and ganglionic globules from 

 the human brain. A, ganglionic globules in the 

 substance of the thalamus, mixed with varicose pri- 

 mary fibres, a, a single ganglionic globule or cell, 

 highly magnified; b, a blood-vessel. B, B, ganglionic 

 globules with processes of various form, as they are 

 met with in the black substance of the crura cereuri. 

 After Valentin. 



