114 



PHYSIOLOGY OF MUSCLES AND NERVES. 



in the nerve is exposed to the irritation, the muscle in 

 this case also describes the curve of its pulsation on 

 the rapidly moved plate of the myograph. Arranging 

 matters so that two curves of pulsation are allowed 

 to describe themselves in immediate sequence, but with 

 the difference that the nerve is irritated in one case at 

 a point near the muscle, but in the other case at a 

 point far from the muscle, two curves will be obtained 

 on the plate of the myograph, which will appear ex- 

 actly alike but yet will not cover each other. On the 

 contrary, they are everywhere somewhat separated 

 from each other, as is shown in figure 29.^ In this 



u (f 



Fig. 29. Pcopagatiox of the kxcitemext witiiix nehves. 



figure, a 6 c is the curve first described, on irritation 

 of the nearer portion of the nerve ; in order to dis- 

 tinguish it from the other it is marked by small nicks ; 

 a' y d represents the curve indicated immediately after 

 the former, but obtained as the result of the irritation 

 of a portion of the nerve remote from the muscle. The 

 second curve is seen to be somewhat separated from the 

 other ; it does not commence so soon after the moment 

 of irritation (which is indicated by the vertical stroke o); 

 that is, a longer time elapsed between the moment of 



' The curves in fig. 21) were describerl when the glass plate 

 moved more rapidh% so that they appear more extended than those 

 represented in figure 18. 



