Conductivity under Geotropic Stimulation. 357 



that in fig. 1. Tlie remainder of the curve shows the injury effects, which 

 are, however, more than counterbalanced by the excitation effects at —90°. 



Uxperiment 2 : K = 6000 ohms. 



Angle to vertical 

 Total resistance 

 Deci'ement of resistance 



0-= 0" -10" -20° -30° -40" -70' -90° 

 7783 7636 7333 6958 6850 6738 6474 6875 

 _ 303 678 786 898 1162 761 



Here the curve is flatter, fig. 9, but the sigmoid character is quite obvious. 



IQ 



20 30 4-0 50 60 70 

 ANGLE WITH VERTICAL 

 Fig. 9. 



80 



90 





Experiment 3 



: E = 



10,000 ohms. 









Angle to vertical 

 Total resistance 

 Decrement of resistance 



0° 



... 10,325 



0° 

 10,325 



-5° -10° 

 10,040 9417 

 285 908 



-20° 

 8869 

 1456 



-30° 

 8691 

 1634 



-40° 

 8552 

 1773 



Angle to vertical 

 Total resistance 

 Decrement of resistance 



-45° 

 8484 

 1841 



-50° 

 8348 

 1977 



-60° -70' 

 7825 7211 

 2500 3114 



-80° 

 7111 

 3214 



-90° 

 6751 

 3574 



+ 90° 

 7007 

 3320 



Although not regularly sigmoid the curve in this case (fig. 10), even after 

 5 hours, shows a perception of the difference between —90° and +90°. The 

 curve up to —40° is qidte regular and as 2| hours had then elapsed from the 

 commencement of the experiment the irregularities are quite comprehensible. 



The upper half of the curve was investigated in the iie.xt two experiments. 



Experiment 4 : li = 4000 ohms. 



Angle with vertical ... 0^ -45 -.50" -60° -70° -80' -90° 



Total resistance ... ' ... 3767 3767 3501 3476 3462 3421 3407 3407 

 Decrement of resistance ... — — 206 291 305 346 367 367 



This curve (fig. 11), although the actual reduction is less than in most 

 experiments, confirms the sigmoid character of the cuive. Variation is to be 



