GENERAL ARRANGEMENT OF THE SYMPATHETIC SYSTEM. 735 



uterine nerves, which go to the uterus and the Fallopian tubes. In the substance of the 

 uterus, the nerves are connected with small collections of ganglionic cells. The sympa- 

 thetic filaments are undoubtedly prolonged into the upper and lower extremities, follow- 

 ing the course of the blood-vessels and distributed to their muscular coat. 



According to the latest researches, the filaments of the sympathetic, at or near their 

 termination, are connected with ganglionic cells, not only in the heart and the uterus, 

 but in the blood-vessels, lymphatics, coccygeal gland, the submucous and the muscular 

 layer of the entire alimentary canal, the salivary glands, pancreas, excretory ducts of 

 the liver and pancreas, the larynx, trachea, pulmonary tissue, bladder, ureters, the entire 

 generative apparatus, suprarenal capsules, thyrnus, lachrymal canals, ciliary muscle, and 

 the iris. In these situations, nerve-cells have been demonstrated by various observers, 

 and it is probable that they exist everywhere in connection with the terminal filaments 

 of this system of nerves. 



Peculiarities in the Intimate Structure of the Sympathetic Ganglia and Nerves. The 

 peculiarities in the structure of the cells and fibres of the sympathetic system are not 

 numerous, nor do they possess very great physiological importance. The free communi- 

 cations between the sympathetic ganglia and the cerebro-spinal nerves, and the differ- 

 ences in the general appearance of certain of these anastomosing branches, lead to the 

 important question of their origin. As a rule, the sympathetic nerves are softer and 

 more grayish in color than the spinal nerves. When there are two branches of commu- 

 nication between a ganglion and a spinal nerve, one of them is white and the other is 

 grayish, and we might infer from this that one, the white, is derived from the spinal 

 system, and the other, from the sympathetic ; but this is a point not yet settled by micro- 

 scopical investigations. It has been conclusively shown, however, that the communi- 

 cating fibres pass in both directions. 



While the branches of the sympathetic contain a large number of the ordinary medul- 

 lated fibres, such as are found in the cerebro-spinal nerves, they also present numerous 

 fibres of Remak, and fine fibres, from 10 ^ 06 to ^-gVs f an inch in diameter, which are 

 regarded by Kolliker as true efferent fibres from the sympathetic ganglia. With regard 

 to the fibres of Remak, we have nothing to add to what we have already stated under 



FIG. 232. Sympathetic gangUon with multipolar cells ; highly magnified. (Leydig.) 



the head of the general structure of the nervous system. These points, with the fact 

 that most of the terminal filaments of the sympathetic are connected with nerve-cells in 

 the substance of the different tissues, constitute the most important anatomical pecu- 

 liarities of the sympathetic nerve-fibres. 



With regard to the cells, which constitute the characteristic anatomical element of 

 the sympathetic ganglia, we shalV have little to say, as their peculiarities at present Beera 



