THE SYMPATHETIC SYSTEM OF NERVES. 541 



cell-substance, a nucleus, and a nucleolus. The sheath or 

 capsule of the ganglion cells cannot be considered in the light 

 of a cell-membrane, but is rather the analogue of the sheath 

 of the nerves; it consists of connective tissue, in which 

 numerous nuclei are distributed. The relation of these cell- 

 capsules to the connective-tissue sheath of the ganglion 

 has been already referred to. Frantzel has demonstrated the 

 presence of a single layer of polygonal flattened cells on the 

 inner surface of the capsules, both in Man and other animals. 

 They sometimes exhibit concentric striation with interspersed 

 nuclei. 



Beale and Remak explained all these peculiarities, which 

 essentially result from the encapsulation of the cells by con- 

 nective tissue, as due to nerve fibres. J. Arnold has en- 

 deavoured to show that a double investment exists in the 

 nerve cells of the Frog, one proceeding from the perineurium 

 of the nerve trunk, and the other from the neurilemma of the 

 afferent nerve fibre. In prepared specimens, as the result 

 of manipulation, the cells may often be seen perfectly naked, 

 and without any trace of a connective-tissue sheath. 



The body or substance of the nerve cells consists of a homo- 

 geneous matrix, in which numerous fine molecules are dis- 

 tributed. Arnold and Bidder have not been able to observe 

 clearly the fibrillar structure described by Max Schultze, as 

 presented by the ganglion cells. 



A moderate number of fine fibres radiating from the nucleus 

 and nucleolus may not unfrequently be seen running through 

 the cell substance. These fibres, of the existence of which I, with 

 Arnold and others, have convinced myself, form, according to 

 Arnold and Courvoisier, plexuses. The existence of such a plexus 

 resulting from the intercommunication of fibres running in the 

 substance of the nerve cells has, however, been disputed by 

 many observers. Kolliker only admits the existence of a 

 plexus on the surface of the cell, which he believes belongs 

 exclusively to the capsule. But, like Arnold, I have observed 

 that these filaments occur in cells that have been detached 

 from their sheaths. Sander ascribes these plexuses to fissures 

 of the cell substance, a view that obviously originates in the 

 examination of carelessly prepared cells. Frantzel believes that 



