CYCLIC MOLECULAR VARIATION 633 



responding substances were elementary, and the experimental 

 arrangements offered no possibility 

 of chemical reaction, it follows that 

 similar responses, in other cases like- 

 wise, are determined, not by some 

 antecedent chemical, but by molecular 

 action, though chemical action may 

 take place as a consequence of their 

 responsive molecular derangement. 



In the first of the series of records 

 in vertical columns (fig. 392) we 

 have : (a) a mechanical record of 

 abnormal response by expansion, 



m 





FIG. 391. Photographic Record of Enhancement 

 of Magnetic Response after Tetanisation 



passing into normal response by con- 

 traction^ after intervening tetanisation, 

 in frog's nerve. In (b) we observe a 

 similar transformation, as seen in the 

 electro-motive response of frog's nerve. 

 The abnormal response by galvano- 

 metric positivity is here converted by 

 tetanisation into the normal negative. 

 Turning next to inorganic substances, 

 and taking the method of Resistivity 

 Variation, we find in (c) the abnormal 

 positive response of tungsten converted 

 by tetanisation into normal negative. 

 Finally (d) where the specimen is tin 

 wire, and the record made by electro- 



FIG. 392. Vertical Series of 

 Records showing Trans- 

 formation of Abnormal 

 into Normal Response 

 after Tetanisation in 

 Living and Inorganic 

 alike in the A phase 



a, Mechanical response of 

 frog's nerve to electric 

 stimulation ; b, Electro- 

 motive response of frog's 

 nerve to thermal stimu- 

 lation ; c, Response by 

 resistivity variation in 

 tungsten to electric radia- 

 tion ; d, Electro-motive 

 response of tin wire to 

 mechanical stimulation. 



