158 



SENSOR1AL FUNCTIONS. 



475. Nervous Ganglia. The nerves as they pass 

 along the different members often form ganglia, or knots, 

 which are small oval masses of nervous substance, con- 

 sisting of the ordinary filaments interlacing each other 

 A ganglion is represented at g, Fig. 97, through which 



Fig. 37. 



Fig. 98. 



the nerve n passes, consisting at its origin of a number 

 of separate filaments, f, and again sub-dividing into many 

 branches, b. 



476. A plexus, or net- work of nerves, is shown by Fig. 

 98. This is formed of four trunks, seen distinct at t, t, but 

 which variously interlace each other, at the same time 

 dividing into branches, before they proceed to their re- 

 spective destinations. 



477. The ganglia appear to be a kind of secondary 

 sensoria, or rather perhaps reservoirs of the nervous 

 power, and in which nervous filaments from the neighbor- 

 ing parts concentrate, or from which these filaments pro- 

 ceed. They are perhaps points, where nerves conveying 

 different kinds of intelligence to the brain meet, and by 

 mingling their influence convey compound sensations to 

 the mind. 



478. But the subject of sensation and perception, as 

 connected with the powers of reasoning and reflection, do 

 not come within the scope of this volume, and we shall 



What are ganglia 2 What is a plexus of nerves? What are the uses 

 of ganglia * 



