THE REACTION OF NORMAL AND ABNORMAL NERVE 153 



In the same manner as the results obtained with excised muscle 

 and nerve, have been formulated into Pfliiger's law of polar stimulation, 

 so may the present results upon human muscle and nerve be combined 

 into the law of unipolar stimulation. But inasmuch as these laws have 

 a different experimental basis, they cannot really be compared with 

 one another unless this comparison be restricted to the causes under- 



j M. gluteus maximuB 



Nerv. ischiadicus 



M. biceps fern. (cap. long.) 

 M. biceps fern. (cap. brev.) 



N. peronetis 

 M. gastrocnern. (cap. extern.) 



M. soleus 

 M. flexor halluc is longus 



M. adductor magnus 

 M. semitendinosus 

 M. semimembranosus 



JV. tibialit 



M. gastrocnem. (cap. int.) 

 M. soleus 



M. flexor digitor. comm. longus 

 N. tibialit 



FIG. 91. NERVES AND MOTOR POINTS IN LOWER EXTREMITY. (Church and 



Peterson.) 



lying them. A clear understanding of the second law requires first 

 of all a brief recapitulation of the following three fundamental data: 



(a) The making of a galvanic current gives rise to an excitation at the cathode, 

 and its breaking to an excitation at the anode. 



(6) The irritability developed at the cathode on the make of the current, is 

 always greater than that generated at the anode on the break. 



(c) The stimulating power of this current is greatest in its area of greatest 

 density. 



