136 Journal of Comparative Neurology. 



the body, the smaller nerve fibers belonged to the organic or 

 vegetative functions of the body, and that the larger nerve fibers 

 were concerned with its psychical activities. The former they 

 called ' sympathetic,' the latter ' cerebro-spinal ' nerve fibers. 

 The scattered cerebro-spinal fibers found in the trunk of the 

 sympathetic and its branches they considered to be sensory 

 fibers." 



Langley (3), in one of the first of his many important re- 

 searches on the sympathetic nervous system (his observations 

 were made on cats, rabbits and dogs), states that "when a piece 

 of the ramus communicans, or of the trunk of the sympathetic 

 down to the first sacral ganglion, or one of the branches run- 

 ning to the solar plexus or to the inferior mesenteric ganglion is 

 teased out, after having been treated with osmic acid for a day, 

 three sizes of medullated fibers at once catch one's attention. 

 The fibers are about 3 ju , S jn and S ju respectively." That the 

 medullated nerve fibers of about 3 // or under are the visceral 

 nerve fibers or true white rami fibers — preganglionic fibers — 

 was clearly shown by Gaskell and Langley. Concerning the 

 larger fibers of the sympathetic, Langley was at first inclined 

 to adopt the view of Bidder and Volkmann, namely, that they 

 were fibers of general sensibility. Further inquiry showed, 

 however, that this in the main was erroneous. And while he 

 states that: "It is well known that sensory fibers are contained in 

 the annuliis of Vieussens, in the splanchnic, and in the branches 

 from the lumbar sympathetic to the inferior mesenteric gang- 

 lion, and that the white ramus arises from the posterior as well 

 as from the anterior roots. Consequently, there was practically 

 no doubt that the white rami contained sensory fibers for the 

 sympathetic system ;" he is forced to conclude, if I understand 

 him correctly, "that many of the larger fibers, and to a vary- 

 ing extent in different nerves, are afferent fibers of some special 

 sense, or subserve local visceral reflexes which escape attention 

 under the conditions of the experiments" made by him. Edge- 

 worth (4), in a paper which appeared about the same time as 

 that of Langley (3) from which I have above quoted, finds in the 

 dog's sympathetic medullated fibers 1.8^^ to 3.6^^ and medu 



