II 



CHANGE OF FORM IX MUSCLE DURING ACTIVITY 



147 



as about 1 in. per see. (1/2 -I/O in.), but later investigations 

 found a much higher velocity. Bernstein, e.g. (.">), gives a velocity 

 of 3 - 2 4'4 ins., on measuring the latent period of the curve 

 of expansion in a given section of the muscle (gracilis and 

 semimembranosus group in frog) when excitation was applied 

 directly to the spot recording itself, and subsequently at as great 

 a distance from it as possible. The experiment was arranged as 

 in Fig. OS. It will be seen to consist in a modification of Aeby's 



I.'K;. (5S. Rate ut' transmission of excitation in muscle. (Bernstein's method.) 



method, in which, however, it is not so much the velocity of trans- 

 mission of the contraction ?w/v, as the underlying <.'<: itation, that 

 is measured, its value being taken as identical with the former. 



As the gracilis and semimembranosus muscles used by Aeby 

 and Bernstein are characterised by a very oblique tendinous 

 intersection, so that each muscle consists as it were of two com- 

 pletely separate portions, in which excitation remains isolated 

 under all conditions, it seemed advisable to repeat the experi- 

 ments with more suitable preparations. Hermann (4) accord- 

 ingly employed the two sartorins muscles of a curarised frog 



