420 SPECIAL HISTOLOGY. 



and are consequently roots of the sympathetic ; in a smaller proportion, 

 however, they might be derived from the sympathetic, and joining them- 

 selves to the spinal nerves are further distributed peripherally together 

 with them. Having entered the main trunk of the sympathetic, the 

 rami communicantes, so far as they are derived from the spinal nerves, 

 almost invariably run, dividing into two or several branches upwards 

 and downwards in it, towards its cephalic and pelvic extremities, being 

 in apposition with the longitudinal fibres of the trunk. In the Rabbit, 

 the- fibres of a given ramus communicant may very frequently be traced 

 as far as the nearest ganglion and beyond it, in separate peripheral 

 branches, but, in general, the course of the individual fasciculi very 

 soon escapes the eye. It may nevertheless be asserted with great cer- 

 tainty, that they all gradually go off 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 ter- 

 mination or origin is never observed in the main trunk itself; which 

 circumstance is also the principal reason why the rami communicantes 

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

 roots. 



Besides the fine and coarser fibres of the rami communicantes, the 

 main trunk of the sympathetic contains other fibres in very great 

 numbers, which are dark-bordered, but pale, finest nerve-tubes measur- 

 ing 0-0012-0-002 of a line, with respect to which I unhesitatingly assert, 

 that they originate in it, and are in no way continuations of the rami 

 communicanteSj 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 sympathetic 

 ganglia under the careful application of dilute soda and compression, 

 that the great majority of the fibres of the rami communic antes 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 communic antes, it is clear, that they must be struc- 

 tures of entirely new formation. This conclusion 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 sympathetic ganglia 

 correspond so far with those of the spinal nerves, that they contain a 



