The Characteristic of Nerve. 



215 



effective at high temperature, ineffective at low temperature, while long- 

 stimuli (energy curve of low number) are effective at low temperature, 

 ineffective at high temperature. 



These results indicate further a point of probably considerable bio- 

 logical significance, inasmuch as the characteristic of frog's nerve at 

 high temperature is found to approximate to that of mammalian nerve. 

 Thus, whereas the characteristic of frog's nerve at room temperature 

 (16° to 18°) is represented by a number of three digits, and that of 

 human nerve at normal temperature (37°) by a number of five digits, 

 the approximate characteristic {i.e., the constant indicating the gradient 

 of a suitable stimulus) of frog's nerve at high temperature (30°) is also 

 expressed by a number of five digits. These and other data are 

 tabulated in the concluding summary. 



Exp. 3. — R = 70,000 co* 



T. 



F. 



V. 



FV. 



5FV 2 . 



c. 







30° 

 5 



-0015 

 -5000 



1-44 

 0-24 



-0022 

 -1200 



0-015 

 0-139 



11910 

 6 



-000073 

 -024250 



f Abolished 

 \ by cooling. 



f Abolished 

 \ by warming. 



For the first trial at 32° the voltage is taken at 1*44, and the minimum 

 effective capacity is sought for and found to be a little below 0'0015. 



In the second trial at 5°, the capacity is taken at 0*5, and the mini- 

 mum effective voltage is sought for and found to be a little below 0'24. 



The first or short stimulus is immediately rendered ineffective by 

 cooling. 



The second or long stimulus is immediately rendered ineffective by 

 warming. 



* In experiments 3 and 4 the characteristic proper has not been determined, 

 but only the constants of a short and long curve of minimal but not optimal minimal 

 stimuli. An optimal minimal stimulus is rendered ineffective by heating and by 

 cooling. The alterations of resistance by alterations of temperature have not been 

 taken into calculation. Such alterations would, however, have only intensified the 

 contrast already apparent between short and long stimuli, in accordance with the 

 following numbers :— 



T. 



■ra 



V. 



FV. 



5FV 2 . 



c. 





E. 















sec. 





30° 



-0015 



1-44 



-0022 



0-015 



16700 



-000052 



50,000 w 



5 



-5000 



0-24 



-1200 



0-139 



4-17 



-034600 



100,000 w 



30° 

 5 



-0007 



1 -oooo 



1-44 

 0-09 



o-ooi 



0-090 



0-007 

 0-040 



17900 



0-391 



-000048 

 -139000 



100,000 a> 

 200.000 w 



