VARIOUS TYPES OF RESPONSE 



103 



radiation, which in its various phases of staircase, uniform 

 and fatigue-decline, is parallel to that just seen in muscle. 

 The phasic change, due to molecular transformation, which 

 I have already pointed out under continuous stimulation, is 

 seen in both these records in the shifting of the base-line. In 

 fig. 64 a under continuous stimulation, we see the mechanical 

 response of muscle passing from a condition of growing 

 contraction into one of relaxation. In the record of individual 

 responses given in fig. 74, the same is seen to take place. 



A similar phenomenon is ob- 

 served in the mechanical re- 

 sponse of Mimosa (fig. 65). 

 When the mode of record, 

 however, is electro-motive, in^ 



FIG. 74. Preliminary Staircase, 

 followed by Fatigue, in the 

 Responses of Muscle (Brodie) 



FIG. 75. Preliminary Staircase, In- 

 crease, followed by Fatigue, in the 

 Response of Galena to Hertzian 

 Radiation 



(Resistivity variation method) 



stead of mechanical, the increasing galvanometric negativity 

 which corresponds to increasing contraction, is found gradually 

 to give place to positivity (fig. 64 b). And finally, when the 

 mode of record is by resistivity-variation, we find, by the 

 shifting of the-base line in fig. 75, that the residual negative 

 variation of resistance at first waxes and then wanes. 



Instances have been given, in which a portion of the in- 

 cident stimulus has been seen to be held latent to do internal 

 work. And from this it is clear that the current assumption that 

 response must always be larger than stimulus is quite un- 



