THE NERVOUS SYSTEM. 179 



that they all gradually go oft' in the peripheral branches of the 

 main trunk, for in the first place all these branches frequently 

 contain, in considerable quantity, the same dark-bordered 

 thicker fibres, as those which are contained in the rami 

 communicantes, and secondly their termination or origin is 

 never observed in the main trunk itself; which circum- 

 stance is also the principal reason why the rami communicants 

 can be regarded not as branches of the sympathetic, but only 

 as its roots. 



Besides the fine and coarser fibres of the rami communi- 

 cantes, the main trunk of the sympathetic contains other fibres 

 in very great numbers, which are dark-bordered, but pale, 

 finest nerve-tubes measuring 00012 — 0'002'", with respect to 

 which I unhesitatingly assert, that they originate in it, and 

 are in no way continuations of the rami communicantes, as has 

 been quite recently supposed, since the discovery of the bipolar 

 ganglion- cells in Fishes. In the Mammalia it is, in fact, 

 extremely easy to prove, by the examination of entire sympa- 

 thetic ganglia under the careful application of dilute soda aud 

 compression, that the great majority of the fibres of the rami 

 communicantes have not the slightest connection with the 

 ganglion-cells, but much rather that they simply pass 

 through the ganglia, and ultimately go off in the peripheral 

 branches. Now, as, besides these fibres in the main trunk, 

 numerous other fibres of the finest kind exist, which can in no 

 way be assigned to the rami communicantes, it is clear, that 

 they must be structures of entirely new formation. This con- 

 clusion appears to be the more legitimate, when it is added, 

 that it is not, as I first and many since have shown, by any 

 means so difficult to demonstrate simple origins of fibres in the 

 sympathetic ganglia of the Mammalia and Amphibia, and that, 

 in the ganglia a considerable portion of fine fibres assume the 

 aspect of so-called convoluted fibres, that is to say, of fibres 

 winding about in various directions through the mass of cells. 

 From what I have seen in the Mammalia and man, the sympa- 

 thetic ganglia correspond so far with those of the spinal nerves, 

 that they contain a preponderance of unipolar, rarely of bipolar 

 cells, differing, however, in this respect, that apolar cells 

 certainly exist in them in more considerable quantity, and the 

 ganglion fibres arising in them are invariably of the finest kind, 



