VARIOUS TYPES OF RESPONSE 



8i 



irresponsive, and only after a period of rest can it exhibit 

 excitation. The same phenomena are observed in the 

 case of the contractile organ of Mimosa. Here also, after 



Fig. 40. — Alternating response ; differences between 

 alternate responses become accentuated. 



erection (expansion) under continuous stimulation, the 

 leaf is irresponsive and only renews its excitability after 

 a definite period of rest. 



As regards this particular reaction in Mimosa, we are 



Fig. 41. — Fatigue-decline in frog's muscle under continuous 

 stimulation. (Brodie.) 



in a position to trace out the various phases through which 

 contraction under single stimulus is reversed to expansion 

 under fatigue induced by continuous stimulation. It has 



