742 



TEE NERVOUS SYSTEM IN GENERAL. 



nerves of organic life, possess a greater quantity of slender tubes than the others. 

 These tubes are commonly designated as the organic nerve-fibres. They also 

 contain fibres of Remak. 



In the spinal ganglia^ the cells are joined to the nerve-tubes. It has been 



Fig. 412. 



Tig. 413. 



MICROSCOPIC GANGLION PROM HEABT 

 OF FROG. 



BIPOLAR GANGLIONIC CELLS AND NERVE- 

 FIBRES, FROM 6ANGLI0N OF FIFTH PAIB 

 IN LAMPREY. 



shown, by dissection and microscopical observation, that the corpuscles com- 

 posing the ganglia or expansions at the origin of the nerves, are all attached ta 

 the superior fibres. The other tubes have none. 



In the cerebrospinal axis, the two substances are equally associated, and 



Fig. 415. 



STELLATE NERVE-CELL, FROM THE NUCLEUS 

 CERVICIS CORNU (POSTERIOR VESICULAR 

 column) OF A FCETUS OF SIX MONTHS. 

 MAGNIFIED 420 DIAMETERS. 



STRUCTURE OP GANGLIONIC NERVE-CELL. 



A, According to Beale ; B, according to Arnold. 

 a. Straight fibre ; 6, double spiral fibre ; c, 

 capsule of connective tissue. 



connected with each other by a prolongation (or single pole) which is inflected 

 in such a manner as to resemble a T or Y (cells with T-shaped fibres), but in a 

 variable manner, according to the region. In the spinal cord and its prolonga- 

 tions into the encephalon, the grey substance occupies the interior ; while it is 

 spread over the exterior of the encephalic lobes, and envelops the white substance. 



