136 PHYSIOLOGY OF MUSCLES AND NKKVKS. 



coming gradually weaker, and finally disappearing en- 



liivly. The law of j)iilsations in the case of dying 

 nerve may also In- represented in tabular form, three 

 >tages of excitability being distinguished; the signs 

 remain the same as in the former table. 



L.\\v OF PULSATIONS IN THE CASE OF DYIM; NI:UVK. 

 (Under the Application of Weak Cum-nts.) 



It is at once apparent that these two eases of the 

 law of pulsation, occurring in different circumstances, 

 lit irely agree. The sequence of the phenomena which 

 occur at the death of the nerve on the applicat ion of cur- 

 rents of little power is exactly the same as that which 

 may be elicited from a fresh nerve by gradually increas- 

 ing the strength <->f the current. In other words, if the 

 nerve is irritated with weak, unvaried currents, these 

 aet on a f re>li nerve, after a time, in exactly the same 

 way as currents of medium .strength, and, after a 

 somewhat longer time, as powerful currents would have 

 aei,-d. In order to understand this, it is accessary to 

 recall our pre\ioiis experiences of the changes in the 

 excitability at the death of the nerve. We found thai 

 iu that case tlie excitability at first rises and attains a 

 maximum before it again falls. Supposing, therefore, 

 a I're.-h in-r\ e is irritated by means of current s of detinil e 



but weak strength, and supposing that this nerve is ex- 

 amined after the lapse of a .-hort time, during which its 

 excitability has risen, it is evident that these weak cur- 



