ANIMAL AND VEGETABLE 149 



tension but of opposite sign at the lower plate, and that 

 impulse would be transmitted throughout the series, with 

 the result that contraction would take place, and the spaces 

 a be compressed and bulge at the sides, while the sarco- 

 lemma would also be contracted. 



The effect would, in fact, be like the compression of a 

 concertina 



Fig. 74. 

 CONCERTINA EXPANDED. 



Fig. 75. 

 CONCERTINA COMPRESSED. 



except that the projections of the bellows would be rounded 

 instead of diagonal, and assume the appearance of the 

 following figure: 



Fig. 76. 



But this would only give us a straight " pull," and as a 

 muscle does not respond to impulse in that way, we must 

 see how Nature overcomes the difficulty, and how discharge 

 or neutralisation is brought about. 



From Fig. 72 (B) we see that the fibrils (and it must 



