232 rnYSiOLOGY of muscles and nerves. 



composed of regularly arranged particles, each of which 

 consists of a small portion of the simply refracting 

 elementary substance, in which is embedded a group 

 of the double-refracting disdiaclasts. Such a particle 

 may be called a onuscle-element. The muscle-fibre 

 would accordingly consist of regularly arranged muscle- 

 elements, the sequence of which, in the longitudinal 

 direction, forms the fibrillae of which mention has been 

 made ; in the lateral direction forms the discs into 

 which the muscle-fibre may separate under certain 

 circumstances. A diagram of a piece of muscle-fibre 

 would, therefore, present an appearance somewhat as 

 in fig. 62, in which each of the small rectangular 

 figures represents a muscle-element. Each such muscle- 

 element is, therefore, in all essential points an entire 

 muscle, for the fibre is but an accumulation of such 

 muscle-elements, each exactly like the other ; and the 

 whole muscle is but a bundle of homogeneous muscle- 

 fibres. In each muscle-element we must, therefore, 

 recognise the presence of all the qualities which belong 

 to the whole muscle. It possesses the capacity of 

 becoming shorter, and at the same time thicker ; and 

 finally — and this is the gist of the question here under 

 discussion — it has the same electric characters as are 

 observable in the entire muscle. 



4. We therefore assume that every muscle-element 

 is the seat of an electromotive force, in virtue of which 

 it is positive on the longitudinal section, negative on 

 the cross-section. If a single muscle-element of this 

 sort were surrounded by a conducting substance, sys- 

 tems of current-curves from the side of the longitudinal 

 section to that of the cross-section would be present 

 within it. If many such muscle-elements are arranged 



