:>04 rnvsioLociY OF MUSCLES AM> NEEVES, 



unchanged, bui tin- pulsations must gradually decrease in 

 strength, anil all effect must finally disappear, just \\h-Mi 

 tin' maximum [' excitability, and tin- death which follows 

 this. pas> tin' lower limit of the excite 1 jmrt'on. 



G. DiiTi:i:r.NCE BET\VI:I:N CLOSING AND OPENING IMX r- 

 TIVE CURRENTS. HKI.MIIHITZ'S ARRANGEMENT (p. 151). 



When an electric current is suddenly closed in a spiral, 

 this not only acts inductively on a neighbouring spiral, but 

 the individual coils of the primary spiral act inductively on 

 each other; an analogous died would occur on the opening. 

 but that the sudden interruption of transmission prevents the 

 development of this opening inductive current in the primar\ 

 coil. The inductive current which originates on the clo>ing 

 of the current being in an opposite direction to the closed 

 i current itself, the former must -weaken '.he latter; th" cnr- 

 i-ent can therefore attain full strength, not at once, but only 

 irradually : but on the opening the current suddenly ceases, 

 Tliis difference in the duration of the closing and opening 

 of the primary current corresponds with differences in the 

 currents induced by them in the secondary spiral, -which are 

 used for the irritation of the nerve. Fi-u.v 7;! exhibits these 

 characters. The ujiper part of tbc fig!ii-e represents the tem- 

 poral course of the main current in the primary spiral of an 

 inductive apparatus; the lower part repn-s -nts the temporal 

 course of the induced currents in the .secondary spiral. The 

 line o ... o ... / represents the duration. The primary current, 

 is dosed at til- moment o. Were the retardatory influence 

 which lias been mentioned not present in the primary spiral, 

 the current would at once attain its full Strength < > .1 \ Imf 

 uuing <' tbat i nil uence it at tains this st ren-t li only gradually, 

 somewhat as shown by the crooked line .">. With ihis-radu- 

 allv occurring current corresponds a closing induct ivr current 

 in the secondary spiral, as is i-eprcseuted by the cu:-ve -1 ; 



