358 ELECTRO-PHYSIOLOGY CHAP. 



the acidity, where it appears, by no means proceeds pari 

 with the progressive development of " rigor," while 011 the other 

 the possibility of recovery of excitability in water-rigored muscles 

 by simple dehydration (2 % NaCl solution) is evidence that the 

 coagulation effects are of another kind than the ordinary forms 

 of rigor. The difference between water-rigor and other forms 

 of rigor is best shown by the fact that frog's muscle, in an ad- 

 vanced stage of water-rigor (an hour or more), exhibits electro- 

 motive action in the same sense arid almost in the same degree 

 as uninjured muscle. If the lower end of a vertically dependent 

 sartorius dips for 30 minutes into distilled water, the muscle 

 will usually, as stated above, show no current, on leading off from 

 the geometrical equator and water-rigored section, or it exhibits 

 a weak inverted current. But if part of the moistened muscle 

 section is warmed in water at 40 C., it exhibits, on leading 

 off, the same electromotive action as before ; the same is the case 

 after crushing or cutting the water - rigored end. There can 

 therefore be no doubt that there is chemically a fundamental 

 difference between the effect of the rigor -like condition pro- 

 duced by distilled water, and the true rigor -mortis of a muscle, 

 the complete development of which seems to preclude the possi- 

 bility of electromotive activity. As therefore electromotive function 

 must certainly be regarded as a property of the living muscle, it 

 is the more remarkable that it should in no way be bound up 

 with the continuance of all vital properties. It can be shown, 

 i.e. that the demarcation current persists in its normal direc- 

 tion and proportions where the muscle has been rendered inexcit- 

 able by chloroform, ether, or amyl. Banke, who was the first to 

 make these observations, always exposed the whole uninjured 

 frog to the vapour of the anaesthetic, and examined various 

 stages of the narcosis. A quicker method is to place the free 

 sartorius, with an artificial cross-section, along with the leading- 

 off electrodes, and a watch-glass of ether, under a bell-jar that is 

 not too small. It may easily be seen that the P.D. between 

 longitudinal and artificial transverse section does not diminish 

 to any perceptible degree, and sometimes even appears to be 

 augmented, when all visible manifestations of excitation have 

 failed in the muscle (19). 



While contractility and conductivity for the most part seem 

 to be abolished in 10 15 minutes, but little diminution 



