104 



ELEMENTS OF HISTOLOGY. [Chap. xiv. 



the nerve-fibres proper, in the cerebro-spinal nerves are 

 grouped into bundles, and these again into anatomical 

 nerve-branches and nerve-trunks. Each anatomical 

 cerebro-spinal nerve consists, therefore, of bundles of 

 nerve-fibres (Fig. 63). The general matrix by which 

 these bundles are held together is fibrous connective 

 tissue called the Epineurium (Key and Retzius) ; this 

 epineurium is the carrier of the larger and smaller 

 blood-vessels with which the nerve-trunk is supplied, 

 of a plexus of lymphatics, of groups of fat-cells, and 

 sometimes of numerous plasma cells. 



137. The nerve-bundles (Fig. 64) are of various sizes, 

 according to the number and size of the nerve-fibres they 

 contain. They are well-defined by a sheath of their 



P 



Fig. 63. From a Transverse Section through the Sciatic Nerve of 

 the Dog. 



ep, Epineurium ; p, perineurhun ; n, nerve fibres constituting a nerve-bundle in 

 cross section ; /, fat tissue surrounding the nerve. (Atlas.) 



own, called perineurium (Key and Ketzius). This peri- 

 neurium consists of bundles of fibrous connective tissue 

 arranged in lamellae, every two lamellae being separated 

 from one another by smaller or larger lymph spaces, 



