110 GENERAL PROPERTIES OF LIVING TISSUES 



take place in what, superficially regarded, is the 

 anodal region (compare page 131, and Fig. 37). 

 The same explanation holds good for the intes- 

 tine (see page 103). The formation of physio- 

 logical anodes and cathodes is well shown in the 

 next experiment. 



Physiological Anodes and Cathodes in Rectus 

 Muscle. Eemove the rectus abdominis muscle, 

 from a curarized frog. Note the tendinous cross 

 bands which divide the muscle from side to 

 side and divide it into parts. Lay the muscle 

 smoothly on a glass slide. Connect the non- 

 polarizable electrodes through a simple key with 

 a dry cell. Place one electrode on each end of 

 the muscle. Close the key. 



On closure, the cathodal side of each division 

 of the muscle will show a sharply defined con- 

 tinued contraction of the ends of the fibres at 

 their insertion in the transverse tendinous bands. 

 On opening, the cathodal contraction disappears, 

 and a similar thickening of the fibres is seen at 

 the anodal side of each division. The twitch of 

 each segment on closure and opening of the cur- 

 rent also starts respectively from the cathodal 

 and anodal ends of each segment. These effects 

 are best seen through a magnifying glass. 



Polar Stimulation in Heart. The muscle cells 

 of the heart are not only of irregular shape, but 



