No. I.] SYMPATHETIC GANGLIA OF VERTEBRATES. 39 



Literature. — The ganglion cells of the frog's sympathetic 

 were first described by Beale and Arnold. In Beale's (9) 

 account the following statement may be found : " In the 

 fully formed cell a fiber comes from the center of the cell 

 {straight fiber), and one or more fibers (spiral fibers) proceed 

 from its surface." " These are wound spirally around the 

 first fiber." Arnold (10) described similar bodies in connection 

 with the nerves in the frog's lung, believing them to be peculiar 

 to this organ. In Arnold's (11, 12) later publications he states 

 that these cells were found generally in the sympathetic system 

 of the frog, and gives a much more detailed account of the 

 straight and the spiral processes. The straight fiber he was 

 able to trace through the protoplasm of the cell to the nucleolus, 

 while the spiral fiber had its origin in a network of fine fibrillae 

 connected with the branches of the nucleolus. (See PI. I, Figs, 

 3, 4, and 6, Virchow's Archive, Vol. XXXII.) Courvoisier (13) 

 corroborated many of the observations made by Arnold. His 

 results may be summed up as follows : The straight fiber 

 begins or ends in the nucleus, while the spiral fiber has its 

 origin in a network which is connected to the nucleolus by 

 " root fibers " — Wttrzelfdden. This network gives origin also 

 to "commissural fibers," which connect the network of adjacent 

 cells. This network was also described by Kollman and Arn- 

 stein (14). On the other hand, Schwalbe (15) stated that the 

 sympathetic ganglia of frogs contained two kinds of cells — 

 bipolar cells, with straight and spiral fibers, the latter arising 

 from the cell body and making only a few turns around the 

 straight fiber, and unipolar cells, with only the straight process, 

 with a prominent capsule, the thickenings or folds of which 

 may simulate a spiral fiber. This latter form Schwalbe believed 

 to be the more common. 



Arndt (16), while not denying the nervous nature of the 

 spiral fiber, suggests that the fibrillar structure of the capsule 

 may in some instances be mistaken for a spiral fiber, inasmuch 

 as the fibrillae of the capsule are now and then arranged trans- 

 versely to the axis of the straight fiber as it leaves the cell. 



Axel, Key, and Retzius (17) made further contributions by 

 showing that the spiral fiber became invested with a medullary 



