150 journal of Comparative Neurology and Psychology. 



Fig. 1. Zeiss, Ocular Ii, Objective 8. — Drawing traced from photo-micro- 

 graph of a transverse section through the control second cervical ganglion of 

 a young white rat twenty days after the operation, showing the character- 

 istics of the normal ganglion. In the center is a clear area representing the 

 dorsal root fibers. Note the size of the large cells, also the large number of 

 small cells. 



Fig. 2. Zeiss, Ocular 4. Objective 8. — Drawing traced from a photo-micro- 

 graph of a transverse section through the "operated" second cervical ganglion 

 of a young rat twenty days after the operation. This section illustrates the 

 alterations which have occurred in the ganglion as a result of division of the 

 nerve. It can be readily seen by comparing Figs. 1 and 2 that there have 

 occurred both an atrophy of the ganglion as a whole and a decrease in the 

 number of the cells. It is apparent at a glance that the cells in the operated 

 ganglion are predominately of the medium size. None are as large as the 

 largest cells seen in the normal ganglion, due to the fact that the cells have 

 already begun to show some atrophy. The most striking feature is the loss 

 of the small cells. 



