TRANSPLANTATION OF THE SPINAL GANGLION 555 



site for the transplantation of nervous tissue than is subcutaneous 

 tissue or muscle. 



After two weeks most of the bizarre formations have disap- 

 peared from the transplanted ganglion. As seen in figure 5, 

 which represents a graft of 17 days' standing, most of the dead 

 cells have been removed; the ganglion has shrunken; and the 

 living cells have been brought close together near the periphery 

 of the ganglion. These cells have a smooth well-defined contour 

 and have a single axon, running toward the center of the ganglion 

 and showing practically no glomerulus. The multiple fine and 

 coarse branches of the cells have disappeared, but there are 

 numerous fine, even-contoured fibers running through the gan- 

 glion in every direction. Only in a small proportion of the cells 

 could any process be demonstrated and this, when present, ap- 

 peared to be a typical axon. In one section (fig. 5) a number of 

 the cells showed axons running toward the center of the ganglion. 



In each of the three grafts of two or three days' duration the 

 surviving cells were multipolar and in each of the thi'ee of 13 to 

 18 days' duration the cells had returned to their normal form. 

 The essential point in these results is that, under suitable experi- 

 mental conditions, unipolar cells may transform themselves into 

 multipolar cells and later return again to their original form. 



The spinal ganglion cells do not undergo peniaanent changes in 

 form after division of their axons at a distant point in a peripheral 

 nerve. A month after di\dsion of the sciatic nerve in dogs the 

 cells in the associated spinal ganglia were of normal form. Nor 

 are such changes produced by cutting the dorsal root a short 

 distance above the ganglion. In connection with a study of 

 Lissauer's tract I have divided the dorsal roots of the sixth and 

 seventh limabar and first sacral nerves proximal to the ganglia 

 in a number of cats, and have taken advantage of the opportunity 

 to study the ganglia associated with the cut roots in four cats 

 which had survived the operation, respectively, 24, 70, 74 and 

 74 days. On comparing these with the normal ganglia, no change 

 in the external form of the cell could be observed. While these 

 experiments show that division of the axon at a distance does not 

 produce permanent changes in the external form of the spinal 



