MUSCULAR CONTRACTION OF HEART. 211 



current is transmitted from one of the binding 

 cups of the base board, up the brass pillar to the 

 coil and downwards through the coil to the mer- 

 cury, which is connected by a wire passing out of 

 the bottom of the cup. While the action is trans- 

 mitted through the coils of the wire, they are sev- 

 erally propelled toward each other, whereby the 

 coil is contracted sufficiently to lift the end of the 

 wire out of the mercury. At the instant this is 

 effected the circuit of the current is broken, and 

 the coil resumes its former length ; the lower end 

 of the wire drops down into contact with the mer- 

 cury again, thus renewing the circuit. This oper- 

 ation being rapidly repeated, the elastic coil is kept 

 quickly vibrating up and down with a peristaltic or 

 churning movement, which is sustained as long as 

 the battery current is transmitted through it. 



The peristaltic movement of the intestines dur- 

 ing the process of digestion, the intermittent spas- 

 modic contraction of the heart and lungs, and the 

 irregular and occasional contractions of the mus- 

 cles may be effected in the same manner. As all 

 molecules are current-changers, there is no lack 

 of these perfect little mechanisms to influence the 

 mechanical action of the opening and closing of the 

 valves of the heart. They also change and modify 

 the intensity of the currents and thereby the rapid- 

 ity and strength of the muscular contractions. 



According to Graham's analysis of animal mus- 

 cle, it appears that the acid phosphate of potash 



