74 SHIGEYUKI KOMINE 



the nerve cells as the result of electrical stimulation, since we 

 know from the work of previous investigators that the nerve 

 cells show a definite alteration as the result of direct stimulation 

 of peripheral nerves (Kodge, Dolley, and others). 



We shall, however, reserve this discussion until further experi- 

 mental data are presented. 



Whatever might be the real cause or causes, we see from this 

 preliminary test that as the result of stimulation the amount of 

 non-protein nitrogen in the brain increases. On account of some 

 defects in our kymograph, it became impossible in the subse- 

 quent experiments to run the machine for long periods continu- 

 ously, and m the later tests we were thus obliged to reduce the 

 maximum stimulation period to six hours. 



EXPERIMENT SERIES 2 



Tn the present experiments the test rats were stimulated for 

 six hours with a current from four batteries. 1 Some of these 

 rats did not fight at all, while others made a good fight. When 

 the data are arranged according to the amount of fighting, we 

 obtain interesting results. 



As will be seen from table 2, after six hours of stimulation those 

 rats which fought give a significantly greater amount of non-pro- 

 tein nitrogen as compared with the controls, while those rats 

 which did not fight give an amount of non-protein nitrogen al- 

 most identical with that for the control brains. It appears from 

 these results that the electrical stimulation alone for a period of 

 six hours is not sufficient to produce a greater accumulation of 

 non-protein nitrogen in the brain, but an emotional disturbance 

 does cause an excessive accumulation of the non-protein nitrogen. 



The present experiment seems to indicate that an increased 

 amount of non-protein nitrogen found in the brain of the rats 

 which were stimulated for more than ten hours, and which did 

 not fight at all (experiment 1) might be mainly due to a some- 

 what increased rate of metabolic activity of the test rats, thus 

 producing a mild inanition. It seems from these data reasonable 



1 Size A, Red Seal Dry Battery, about 30 amperes, when fresh. 



