36 



PHYSIOLOGY OF MUSCLES AND NERVES. 



small plate soldered on to the surface of the German 

 silver sj)ring the current is closed and interrupted. An 

 apparatus of this kind is called a sliding inductorium. 

 It is only necessary to attach the ends of the coil i to 

 the muscle, and to insert the chain between the columns 

 a and g. The action of the hammer then at once 



commences ; the inductive cur- 

 rents generated in c pass through 

 the muscle, which contracts te- 

 tanically. 



Instead of connectinor coil c 

 immediately with the muscle, it 

 is better to carry the wires from 

 the coil to the two clamps h and 

 c in the apparatus shown in fig. 

 14, which is called a tetaiiising 

 key. Two other wires pass from 

 these same clamps h and c to the 

 muscle. When the inductive ap- 

 paratus is in action the muscle is 

 put into a tetanic condition. But 

 as soon as the lever d is pressed 

 down, so as to connect h and c 

 together, the current of coil i is 

 Fio. 14. Tktanising key of enabled to pass through this le- 



DU lioiS RliYiMOND. rrii 1 7 1- i n 



ver. Ine lever a bemo- made of 

 a short and thick piece of brass, which offers hardly any 

 resistance to the current, while the muscle on the con- 

 trary offers great resistance, very little of the current 

 passes through the muscle, but nearly all through the 

 lever cL The muscle, therefore, remains at rest. As 

 soon, however, as the lever d is again raised, the in- 

 ductive currents must again pass through the muscle. 



