212 



Dr. A. D. "Waller. 



constant, there is no effect at all, a test is taken in the opposite direc- 

 tion, with double the voltage and one-fourth the capacity, i.e., with 

 the constant of the original energy curve multiplied by eight. 



The second plan affords a rapid survey of the whole field of stimula- 

 tion. When energy is varied by variation of voltage at any given 

 capacity, it varies as voltage squared, and the constant of its curve is 

 augmented directly as the voltage. The step from maximal to sub- 

 minimal stimulation is comparatively large when we test at a series of 

 diminishing voltages, and a voltage is soon reached at which no 

 increase of capacity, however great, can bring out an effective stimulus, 

 the constant of the energy curve being lowered as capacity is increased. 



The third plan is useful only for closer determination of an optimum 

 gradient, when the range within which it is to be sought for is approxi- 

 mately known. When energy is varied by variation of capacity at any 

 given voltage, it varies directly as capacity, but the constant of its 

 curve diminishes as capacity is increased, i.e., a small increment of 

 energy is obtained at a reduced gradient, as compared with a large 

 increment of energy at a raised gradient obtained by increase of 

 voltage. 



Exp. 1. — Nerve-muscle Preparation. Eesistance of Nerve + Electrodes 



= 150000 w. 



I 



Capacity 

 in 

 micro- 

 farads. 



Pressure 

 in 

 rolts. 



Quantity 

 in 

 micro - 

 coulombs. 



Energy 

 in ergs. 



Con- 

 stants. 



Time of 

 fall of 

 energy to 

 5 value. 



Con- 

 traction. 





F. 



T. 



FY. 



5FV 2 . 



C. 



h- 







-0004 

 0-0016 



1-44 

 0-72 



0-0005761 

 '001152 J 



-00415 



j 20850 

 \ 2606 



-000042 

 -000168 



small, 

 large. 





-ooio 



-0040 



0-72 

 36 



0-00072 1 

 0-00144 J 



'00259 



| 4170 

 1 521 



-000104 

 -000416 



small, 

 large. 





'0025 



o-oioo 



0-36 

 0-18 



-0009 \ 

 -0018 J 



-00162 



f 834 

 \ 104 



-000260 

 -001040 



small, 

 large. 



Opt. 



0-0080 

 -0320 



0-18 

 0-09 



0-00144 \ 

 0-00288 J 



-00130 



r 130 



I 16 



"000832 

 -003328 



small, 

 none. 





-0800 

 -3200 



0-09 

 0-045 



-0072 \ 

 "0144 J 



-00324 



f 6-5 

 \ 0-8 



-008320 

 -033280 



small, 

 none. 



4 



-0400 



o-oioo 



-0025 



0-09 

 0-18 

 0-36 



-0036 ] 

 -0018 } 

 -C009 J 



-00159 



f 834 

 \ 104 

 I 13 



0-000260 

 -001040 

 -004160 



none, 

 large, 

 small. 



