TRANSPLANTATION OF THE SPINAL GANGLION, 



WITH OBSERVATIONS ON THE SIGNIFICANCE 



OF THE COMPLEX TYPES OF SPINAL 



GANGLION CELLS 



S. WALTER RANSON 

 From the Anatomical Laboratory of the Northwestern University Medical School 



FIVE Fir.HRES 



One may no longer look upon the spinal ganglion as contain- 

 ing only simple unipolar cells with T-shaped axons. The re- 

 searches of the past ten years have shown that from this funda- 

 mental type all sorts of variations occur. A glance at Dogiel's 

 ('08) monograph shows how great is the nmnber of such variations 

 and how completely they baffle any attempt at logical classifica- 

 tion. From the cell body may arise short, thick processes, or 

 fine fibers ending in pyriform or spherical expansions. Other 

 cells present elevated loops of protoplasm which are attached to 

 the cell body at both ends. When such loops are numerous, 

 the cells are spoken of as fenestrated. In other cases the axon 

 at or near its origin from the cell may be broken up into a nmnber 

 of fibers, which unite with each other to form a plexus, and which 

 are finally assembled into a single axon. Other axons give off 

 collaterals with terminal enlargements called end-bulbs. 



Although these complicated structures have been much dis- 

 cussed, we are still in doubt as to their functional significance. 

 In this connection, we should not forget that, although obscured 

 by all these variations, the fundamental characteristic of the spinal 

 ganghon cefl remains unchanged; i.e., the cell possesses an axon 

 which, dividing dichotomously, puts the cell into relation with 

 the periphery on the one hand and the central nervous system 

 on the other, and, so far as we understand the physiology of the 

 spinal gangUon, this simple type seems to answer all the require- 

 ments for the conduction of afferent unpulses. 



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