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AN AMERICAN TEXT- BOOK OF PHYSIOLOGY. 



The sections indicate that the cytoplasm, together with the enclosed nucleus 

 and nucleolus, as •well as the nuclei of the enclosing capsule of the cell, have 

 all suffered change by this treatment. The stimulus was applied for only 

 fifteen seconds of each minute, the remaining forty-five seconds being given 

 to rest. In this way the cells here figured had been stimulated over a period 

 of five hours. The nuclei of the sheath are flattened, the cytoplasm of the 



Fig. SI.— Two sections, A and /;, from the first thoracic spinal ganglion of a cat. B is from the gan- 

 glion which bad been electrically stimulated through its nerve for live hours. A, from the correspond- 

 ing resting ganglion, The shrinkage of the structures connected with the stimulated cells is the most 

 marked general change, n, nucleus; n, s, nuclei of the capsule; v, vacuole; X 500 diameters (Hodge). 



nerve-cells somewhat shrunken and vacuolated. With osmic acid the nuclei 

 of the stimulated cells stain more darkly and the cytoplasm less darkly than 

 in a resting cell. Tn the nerve-cells the nucleus is shrunken and crenated, 

 and the nucleolus is also diminished in size. 



In the first experiments the attempt was made to demonstrate a measur- 

 able change within the nerve cell-bodies as the result of stimulation. Assum- 

 ing the nuclei of these cells to be approximately spherical, and calculating 

 their volume as spheres, the shrinkage amounted to that shown in the follow- 

 ing table : 



