332 ELECTRO-PHYSIOLOGY CHAP. 



muscle is too slow and inadequate a process as was pointed out 

 above. Yet in favourable cases the autonomous up change is 

 exhibited in a physiological homodromous current, that makes its 

 appearance at break, if the now kathodic end of the muscle is put 

 in circuit with the centre of the muscle. 



" The fact that muscle-, like nerve -fibre, fails to react to trans- 

 verse passage of current, obviously signifies that living matter is 

 not intrinsically the same living continuum in the transverse as in 

 the longitudinal direction ; as appears from optical polarisation 

 phenomena, and from the relations of elasticity. The failure in 

 reaction is perhaps due to the fact that the antagonistic points at 

 which the current leaves and enters are too closely approximated 

 in the structural elements traversed at right angles by the current. 



" When a strong foreign current has been flowing longitu- 

 dinally through an uninjured muscle for so long that the 

 persistent kathodic contraction has already expired, the persistent 

 anodic contraction (supra) will appear when the current is broken, 

 and may extend over a large tract of the muscle, and last for a 

 considerable period. If the current is then closed again, it will 

 act as an inhibitory stimulus on the contracted muscle, which at 

 once relaxes completely. The anodic stimulus of the foreign 

 current, which tends to upward alteration in the substance, now 

 works against the rapid autonomous down change that prevailed 

 after break at the point of entrance, and substitutes an up change. 

 Owing, however, to the previous exhaustive allonomous descending 

 alteration, there is not inevitably a new closure contraction at 

 the point of exit. 



" Just as the persistent opening contraction of a muscle may 

 be inhibited by renewed closure of the current, another contraction 

 depending on autonomous down change may be inhibited by the 

 action of an anodic current. If, just at the beginning of systole, 

 a stronger current is sent in through one brush-electrode, the 

 point of which rests upon the frog's heart (exposed with uninter- 

 rupted circulation), while the other electrode forms contact with, 

 e.g., the skin of the throat, a more or less extended diastole of the 

 heart-wall, starting from the point where the current enters, will 

 make its appearance. The commencing autonomous down change 

 is immediately converted, by the anodic action of the current, 

 into an allonomous up change, and the relaxed part of the cardiac 

 wall swells out freely in consequence of blood -pressure. The 



