31 8 THK GROWTH OF THE BRAIN. 



cats by electrically stimulating the peripheral trunks 

 of mixed spinal nerves ; the condition of the spinal 

 ganglion cells, with which the sensory fibres were 

 connected, was then examined ; the cells in the gang- 

 lion on the side of stimulation being compared with 

 those from the opposite ganglion of the same animal. 

 As a result of stimulation in this way, the fatigued 

 cells appear shrunken, and their reaction to staining 

 reagents changed, thus showing a chemical alteration. 

 The shrinkage involves the nuclei of the capsule sur- 

 rounding these elements as well as the nucleolus, 

 nucleus, and cytoplasm of the cells themselves, the last 

 becoming vacuolated. In the accompanying figure (73) 

 these differences can be seen by comparing the fatigued 

 cells B with the normal cells A. 



As the most clearly marked differences were found 

 in the nuclei, these were further studied. Their volume 

 decreases according to the length of time that they 

 are stimulated, as indicated in Table 58. 



TABLE 58. SHOWING THE DECREASE IN THE VOLUME OF 

 THE NUCLEUS OF STIMULATED SPINAL GANGLION CELLS 

 OF CATS. FIFTEEN SECONDS' STIMULATION ALTERNATING 

 WITH FORTY-FIVE SECONDS' REST. (Hodge.} 



The curve shown by the broken line in Fig. 74 

 expresses the same facts as have just been given in 

 Table 58. 



