194 



PHYSIOLOGY 



CHAP. 



He saw that conductivity returned a few seconds after the pressure 

 was removed, provided it had not been excessive nor unduly pro- 



Fni. 127. Myograms of frog's gastrocnemius (1) with electrical stimulation ; (2) with break shocks 

 at an interval of 4 sees. (Ducceschi.) In both tracings a weight was applied at ^ the value 

 being marked in grammes ; at -^- the compression ceased. 



longed (Fig. 127). If, while the frog's gastrocnemius was being 

 tetanised by an interrupted current applied to the sciatic, the 

 nerve was compressed below the point of excitation, the trans- 

 mission of the impulses was partially inhibited, and the almost 



FIG. 128. The marks on these tracings correspond to those of the preceding figure. 

 At b and c the nerve was tetanised. 



tonic contraction of the muscle was transformed into a clonic 

 contraction (Fig. 128). The effects of graduated compression on 

 conductivity differed according as chemical, mechanical, or electrical 



