226 Prof. Bose and Mr. Das. Physiological Investigations with 



Fig. 9. — Antagonistic action of alkali and acid. Arrest of response in contraction under 

 NaOH(t), restoration and final arrest in expansion under lactic acid(t '). 



8. Effect of "Fatigue " on Response. 



With Mimosa, after each excitation the recovery becomes complete after 

 a resting period of about 15 min. With this interval of rest the successive 

 responses for a given stimulus are equal, and are at their maximum. But 

 when the resting interval is diminished the recovery becomes incomplete, 

 and there is a consequent diminution of amplitude of response. There is 

 thus an increased fatigue with diminished period of rest. This is illustrated 

 in fig. 10, where the first two responses are at intervals of 15 min. ; the 

 resting interval was then reduced to 10 min., the response undergoing a 



Fig. 10. 



Fig. 10. — " Fatigue " induced by shortening intervening period of rest. 



Fig. 11. — Action of constant current in removal of fatigue by hastening recovery ; 

 N, curve of fatigue j C, after passage of current. 



