NERVE-CELLS. 



69 



Organ of Golgi (Fig. 73). At the point where muscles and 

 their tendons join, the tendon-bundles 

 present an enlargement, between the 

 fasciculi of which one, two, or more 

 nerve-fibers enter to terminate in an 

 arborization which is characterized 

 by varicosities. The term " organ 

 of Golgi " includes the enlargement 

 and the arborizations. 



Muscle-spindles. These are de- 

 scribed under the name neuro-mus- 

 cular spindles. A spindle is a fusi- 

 form body having a length of from 

 0.75 mm. to 4 mm. Externally is a 

 sheath of connective tissue within 

 which is the interposed bundle, con- 

 sisting of from ten to twelve muscle- 

 fibers, resembling embryonic fibers. 

 The nerve-fibers distributed to these 

 spindles divide, and the axis-cylin- 

 ders clasp the fibers by flattened ex- 

 pansion. None of these spindles has 

 been found in either the muscles of 

 the eye or the tongue. They are con- 

 sidered to be sensory nerve-endings in 

 the muscles. 



Nerve-cells (Figs. 75-78). 

 This kind of nervous tissue is also 

 called gray, cineritious, cellular, 

 vesicular, nervous matter. 



Nerve-cells are of different sizes, 

 varying from 4 p. to 150 /j>. Their 

 shape also varies greatly, some being 

 ovoid, while others are very irregular 

 in outline. Each cell contains a large, 

 distinct, and spheroidal nucleus, with 

 a single nucleolus, and fibrillated pro- 

 toplasm. In the protoplasm are some- 

 times angular granules, Nissl's gran- 

 ules, which are stained by methylene- 

 blue. 



From nerve-cells are given off two 

 kinds of processes : axis-cylinder pro- 

 cesses or neuraxe,, and protoplasmic 



processes or dendrites. These are the preparation of tissue stained in 

 principal elements in nerve-fibers, methyiene-blue (Huber and De 



,, r Witt, Jour, of Comp. A enrol., vol. 



Ine number 01 these processes or x .). 



