Ranson, Spnial Nerves. 109 



took to demonstrate their presence in teased preparations but 

 came to the conclusion that "Apolar cells do not occur in the 

 spinal ganglia of frogs in any considerable numbers, none having 

 been found." 



3. Interrelations among the spinal ganglion cells. — The spinal 

 ganglion is not to be regarded as an aggregation of more or less 

 spherical cells each independent of the others and connected only 

 with its central and peripheral processes; but is in reality a com- 

 plicated mass containing the ramifications of dendrites and axis 

 cylinders, forming exceedingly intricate intercellular meshworks 

 and pericellular baskets, the cells in this way being brought into 

 close functional relations with each other. Moreover there are 

 sympathetic fibers which enter the ganglion via the ramus com- 

 municans to join in the formation of these baskets. 



Aronson ('86) was the first to describe the pericellular baskets 

 in the spinal ganglion and his observations were confirmed by 

 Cajal ('90). The latter investigator regarded them as ramifica- 

 tions of fibers from the sympathetic system. It was Dogiel 

 however who first cleared up our notions on this point by describ- 

 ing a variety of cell ("Type II") which has for its sole function 

 the establishment of intraganglionic connections. 



Spirlas ('95) called attention to the existence of collaterals 

 arising from the processes of the embryonic spinal ganglion cells. 

 The observations were confirmed upon adult material by Dogiel 

 in 1896: "from the processes of many large and small ganglion 

 cells, before their division into two fibers, one, two or three col- 

 laterals of varying thickness are given off which at a greater or 

 less distance from their cells break up into fine threads." Levi 

 ('05) has followed the embryological formation of these collaterals. 



In 1896 Huber described a variety of spinal ganglion cell from 

 the axon of which recurrent collaterals are given off. These 

 run back and end in disks upon the cell from which the axon arose. 



Still another means of intercommunication between the spinal 

 ganglion cells is found in the dendritic processes of the multipolar 

 cells and the more numerous unipolar cells of Cajal, possessing 

 fine dendritic branches with spherical endings which may either 

 be in connection with the immediate pericellular basket or may 

 run for considerable distances in the intercellular spaces to make 

 connections in other parts of the ganglion. 



Expressed in other words, the relations are as follows. Sym- 



