76 SHIGEYUKI KOMINE 



to conclude that as a result of great emotional disturbance the 

 circulation of the blood is accelerated, and as a consequence the 

 cell metabolism of the brain is also accelerated, thus producing a 

 greater amount of metabolites in the brain. 



EXPERIMENT SERIES 3 



Thus far the test rats did not f ght vigorously, owing to their 

 lack of response to the electrical stimulus. We found later that 

 when their tails are lightly pricked with a sharp needle they at 

 once begin fighting. By such a simple procedure, accompanied 

 by the electrical stimulus, the rats are made to fight severely, 

 at the same time squealing and biting each other. When once 

 such a violent fight starts the periodic shock is irritating enough 

 to make the fight continue until one rat becomes exhausted and 

 tries to avoid its opponent's attacks. The amount of non-pro- 

 tein nitrogen was determined for those rats which had such a 

 very severe fight for from one to four hours. The results are 

 given in table 3. ■ 



The results obtained from the eight independent experiments, 

 using sixteen test rats, show clearly that the amount of non-pro- 

 tein nitrogen in the brain increases as the result of severe fight- 

 ing when compared with that obtained from the control brain. 

 The amount of non-protein found is, however, irregular and there 

 is no precise indication of a proportional increase with prolonga- 

 tion of the fighting period. In fact, in one instance (the third in 

 table 3) a large amount of decrease is shown as the result of 

 severe fighting for three hours. This decrease in the amount of 

 non-protein nitrogen might have been the result of a complete 

 exhaustion. These irregularities in the amount of non-protein 

 nitrogen found in the brains of test animals may be due to the 

 fact that there are considerable individual differences as to the 

 behavior during experimentation. Some rats are very aggres- 

 sive and may continue violent fighting without cessation, while 

 there are instances in which the rats fight severely for a few sec- 

 onds, then stop fighting for some time, only to resume again. 

 Still more important in accounting for the irregularities is the 



