130 



TEXT-BOOK OF PHYSIOLOGY. 



we do so, in fact. When the cathode is applied, and the current is 

 made and broken, we obtain a cathodic make contraction and a cathodic 

 break contraction; when the anode is applied, and the current is made 

 and broken, we obtain an anodic make contraction and an anodic 

 break contraction. These four contractions .are, however, of very 

 different strengths; tlie "cathodic make contraction is by far the 

 .strongest; the cathodic break contraction is by far the weakest; the 

 cathodic make contraction is stronger than the anodic make con- 

 traction; the anodic break contraction is stronger than the cathod it- 

 break contraction. Or, otherwise regarded, if, instead of comparing 

 the contractions obtained with a sufficiently strong current, we ob- 

 serve the order of their appearance with currents gradually increased 



M. biceps brachii. 



M. brach. anticus. 



N. medianus 



M. pronator teres. 



M. flex, digitor. commun. profund. 

 M. flex, carpi radialis. 



M. flex, digitor. sublim. 



M. flex. dig. subl. (dig. ind. et min.) 

 M. flex. poll, longus. 



N. ulnaris. 



M. flexor carpi ulnaris. 



N. ulnaris. 



FIG. 57. MOTOR POINTS OF THE MEDIAN AND ULNAR NERVES, WITH THE MUSCLES 



SUPPLIED BY THEM. 



from weak to strong, % we shall find that the cathodic make contraction 

 appears first, that the cathodic break contraction appears last, and 

 the formula of contraction for man reads as follows : 



"Weak current, K. C. C. 



Medium current, K. C. C. A. C. C. A. O. C. 



Strong current, K. C. C. A. C. C. A. O. C. 



K. O. C. 



The constant or the galvanic current is frequently used for thera- 

 peutic and diagnostic purposes. In accordance with the statements 

 above quoted, one electrode should be applied to the part to be in- 

 vestigated, the other to some indifferent region. The electrode con- 



