io 4 RESPONSE IN THE LIVING AND NON-LIVING 



CHAPTEE XIII 



INORGANIC RESPONSE MOLECULAR MOBILITY : 

 ITS INFLUENCE ON RESPONSE 



Effects of molecular inertia Prolongation of period of recovery by over- 

 strain Molecular model Reduction of molecular sluggishness attended 

 by quickened recovery and heightened response Effect of temperature 

 Modification of latent period and period of recovery by the action of 

 chemical reagents Diphasic variation. 



WE have seen that the stimulation of matter causes 

 an electric variation, and that the acted substance 

 gradually recovers from the effect of stimulus. We 

 shall next study how the form of response-curves is 

 modified by various agencies. 



In order to study these effects we must use, in 

 practice, a highly sensitive galvanometer as the recorder 

 of E.M. variations. This necessitates the use of an 

 instrument with a comparatively long period of swing 

 of needle, or of suspended coil (as in a D'Arsonval). 

 Owing to inertia of the recording galvanometer, however, 

 there is a lag produced in the records of E.M. changes. 

 But this can be distinguished from the effect of the mole- 

 cular inertia of the substance itself by comparing two 

 successive records taken with the same instrument, in 

 one of which the latter effect is relatively absent, and 

 in the other present. We wish, for example, to find out 



