500 Prof. J. C. Bose. Influence of Electric 



that the point of stimulation in this ease is chosen to lie on the nerve at the 

 middle or indifferent region. But the responding muscle is at one end, not 

 very distant from the electrode applied on the tendon. It is, therefore, 



Fig. 8. — Ineffectively transmitted salt-tetanus becoming effective under heterodromous 



current. 



Fig. 9.- — Direct and after-effect of homodromous current. Transmitted excitation 

 (salt-tetanus) arrested under homodromous current ; on cessation of current there 

 is a transient enhancement above the normal. 



necessary to find out by separate experiments any variation of excitability 

 tbat might be induced in the muscle by the proximity of either the anode or 

 the kathode, and make allowance for such variation in interpreting the results 

 obtained from investigations on variation of conductivity. 



In the experimental arrangement employed, the heterodromous current is 

 obtained by making the electrode on the spine kathode and that on the tendon 

 anode. The depressing influence of the anode in this case may be expected 

 to lower, to a certain extent, the normal excitability of the responding muscle. 

 Conversely, with homodromous current, the tendon is made the kathode and 

 under its influence the muscle might have its excitability raised above 



