IIO NORMAL HISTOLOGY. 



3. We find within the lamellar sheath and be- 

 tween the nerve-fibres composing the fascicle, in the 

 first place, prolongations inward of the tissue com- 

 posing the lamellar sheath ; and, second, fine fibril- 

 lated fibres and flattened cells which lie in the 

 interstices between the nerves and fibres. This tis- 

 sue is called the intra-fascicular connective tissue. 

 Blood-vessels penetrate the lamellar sheath of the 

 medium-sized and larger nerves, and a very long- 

 meshed and abundant capillary net-work is formed 

 in the intra-fascicular connective tissue. Lymphatic 

 channels and spaces are also abundant within the 

 nerves, so that the fibres are bathed in nutritive 

 fluids. 



Termination of Medullatcd Nerve-fibres 



i. In the Nerve-centres. We find in the nerve- 

 centres, nerves which have no neurilemma, and 

 others in which both neurilemma and medullary 

 sheath fail the so-called naked axis cylinders ; we 

 find, further, extremely delicate filiform structures 

 which are believed to be the primitive nerve-fibrils. 

 The axis cylinders of the nerves being, as above 

 stated, processes of nerve cells, the nerve-fibres, as 

 we trace them back into the centres, must sooner or 

 later join cells. Their exact mode of connection 

 with the cells is not in all cases sufficiently well un- 

 derstood ; but it is believed that they either join 

 the cells in the form of naked axis cylinders, or, in 



