I 56 THE TISSUES. 



served fine chromatophile granules and a large nucleus and nucleolus. 

 From the cell-body there proceed a varying number of dendrites 

 which branch and rebranch and terminate, as a rule, near the cell- 

 body, forming plexuses in the ganglia. The neuraxis arises either 

 directly from the cell-body from an implantation cone, or from one of 

 the dendrites at a variable distance from the cell-body. (Fig. 1 17.) 

 In nearly all ganglia a few unipolar or bipolar cells are to be found. 

 In the sympathetic nervous system of amphibia the sympathetic 

 neurones.are unipolar ; the single process present is the neuraxis. 



A most important result of the more recent investigations on the 

 nervous system is the theory of the independence of the neurone. 

 Each neurone develops from a single cell (neuroblast), and func- 

 tionates as an independent cell under physiologic and pathologic 

 conditions. Only very rarely has any direct connection between 

 two neighboring neurones been demonstrated, so rarely that the 



Fig. 117. Neurone from inferior cervical sympathetic ganglion of a rabbit ; methylene- 



blue stain. 



scattered observations at hand do not vitiate the above statement. 

 Recent investigations have, however, shown that, while a neurone is 

 a distinct anatomic unit, it is always found associated with other 

 neurones. Nowhere in the body of a vertebrate does one find a 

 neurone completely disconnected from other neurones. This asso- 

 ciation of one neurone with one or several other neurones is always 

 effected by a close contiguity existing between the telodendria 

 (end-branches) of the neuraxis of one neurone with the cell -body or 

 dendrites of one or several other neurones. The telodenclrion of 

 the neuraxis of one neurone may form a feltwork inclosing the cell- 

 body of one or several neurones, forming structures known as 

 terminal baskets or end-baskets, or the end ramifications of the 

 neuraxis of a neurone may come in very close proximity to the 

 end-branches of the dendrites of one or several neurones. By this 

 contiguity of the telodendria of the neuraxis of one neurone with 



