THE MOLECULAR THEORY OF EXCITATION 



603 



In fig. 370 is seen an example of the same thing in tungsten, 

 where recovery from the effect of electric radiation is hastened 

 by a tap. 



It has been shown that the normal response by negativity 

 in living tissues is liable to reversal under very feeble 

 stimulation. This is better observed when the tissue is 

 not highly excitable ; because in this case it is easy to 

 adjust the intensity of stimulation, so as to fall below the 

 critical value for excitation. 

 It is very interesting to ob- 

 serve similar opposed effects, 

 under feeble and moderately 

 strong stimulations, in the re- 

 sponse of inorganic substances. 

 For the reason just mentioned, 

 it is desirable to select a sub- 

 stance for this purpose, which 

 possesses a moderate degree 

 of sensibility. Using a mass 

 of tungsten particles, I found 

 that under strong intensity 

 of electric radiation brought 

 about by placing the radiator 

 within a short distance of the 

 substance the response was 

 by the normal negative varia- 

 tion, or diminution of resist- 

 ance. But when the intensity 

 of stimulus was diminished by placing the radiator at a 

 greater distance, then the response was converted to positive. 

 A record of this abnormal effect under feeble stimulation will 

 be given later. 



Thus, having observed molecular response and its varia- 

 tions by the Magnetic and Resistivity Methods of record, we 

 now proceed to study the transmission of the state of 

 excitation. We have seen that the essential condition of the 

 transmission of excitation in living tissues lies in the 



FIG. 370. Photographic Record 



of Response of Tungsten 

 The incomplete recovery is hastened 

 by application of tap at points, 

 marked with downward arrow. 

 Cf. fig. 364- 



