82 RESPONSE IN THE LIVING AND NON-LIVING 



Is response found in inorganic substances ? 1 It is 

 now for us, however, to examine into the alleged super- 

 physical character of these phenomena by stimulating 

 inorganic substances and discovering whether they do 

 or do not give rise to the same electrical mode of re- 

 sponse which was supposed to be the special character- 

 istic of living substances A We shall use the same apparatus 

 and the same mode of stimulation as those employed in 

 obtaining plant response, merely substituting, for the stalk 

 of a plant, a metallic wire, say ' tin ' (fig. 50). Any other 

 metal could be used instead of tin. 



Experiment on tin, block method. Let us then take 

 a piece of tin wire 2 from which all strains have been 

 previously removed by annealing, and hold it clamped 

 in the middle at C. If the strains have been success- 

 fully removed A and B will be found iso-electric, 

 and no current will pass through the galvanometer. 

 If A and B are not exactly similar, there will be a 

 slight current. But this will not materially affect the 

 results to be described presently, the slight existing 

 current merely adding itself algebraically to the current 

 of response. 



If we now stimulate the end A by taps, or better 



1 Following another line of inquiry I obtained response to electric 

 stimulus in inorganic substances using the method of conductivity 

 variation (see ' De la Generalite des PhSnomenes Moleculaires Produits 

 par 1'Electricite sur la Matiere Inorganique et sur la Matiere Vivante,' 

 Travaux du Conyres International de Physique, Paris, 1900 ; and also ' On 

 Similarities of Effect of Electric Stimulus on Inorganic and Living 

 Substances,' British Association 1900. See Electrician). To bring out 

 the parallelism in all details between the inorganic and living response, 1 

 have in the following chapters used the method of electro-motive variation 

 employed by physiologists. 



2 By l tin ' is meant an alloy of tin and lead used as electric fuse. 



