li)-i PHYSIOLOGY OP MfSCLl-S .\M> NERVES. 



the direction from the positive to the negative point ; 

 hut that, if the feet are both positive, or both negative, 

 the current, passes lY'>in tin- more to the less positive 

 point, or from the less to the more negative point. 

 From the curves in A and B, fig. 51, which show the 

 tensions, the currents indicated in fig. 50 may therefore 

 easily be discovered. 



3. Once more let ns take a muscle, the fibres of 

 which are parallel, and cut a piece out of this, but in 

 such a way that the cross-section, instead of being at 

 right angles to the direction of the fibres, is obliquely 

 directed toward the latter. A piece of this sort may be 

 called a muscle-rhombus ; if the cross-sections are 

 parallel to each other, it is a regular muscle-rhombus ; 

 if otherwise, an !>>> yilar muscle-rhombus. In such a 

 muscle-rhombus, the distribution of the tensions, and, 

 consequently, the form of the iso-electric curves, is 

 much more complex than in a muscle-prism. In this 

 case the curves are not, as in a muscle-prism, parallel, 

 but are sometimes of very complex form. 



It is true that in this case also there is the main 

 distinction between the longitudinal section, or outer 

 surface of the muscle-rhombus, and the cross-sections. 

 The former arc always positive, the latter negative. 

 But both in the longitudinal and cross-sections a 

 difference is noticeable between the nlituse and the 

 acute angles. The positive tension is greater at the 

 obtuse than at the acute angles of the longitudinal 

 section; and, similarly, the negative tension is greater 

 at the acute than at the obtuse angles of the cross- 

 sections. Consequent ly, a peculiar displacement of the 

 tension-curves, of which tig. -~>2 is intended as a re- 

 presentation, takes place in a regular muscle-rhombus, 



