SOME RECENT WORK UPON MUSCLE AND NERVE. 439 



of this discrepancy has been known for some time but has 

 acquired a new interest from the animated controversy 

 which is still going on between Schenk and Kaiser with 

 reference to its meaning. There are at least two possible 

 interpretations of the discord in the results. The first 

 is that the muscular events recorded are not the same ; 

 both histories may be correct, but the mechanical condition 

 of tension present when the isometric record is obtained, 

 may be a disturbing factor and thus alter the muscular 

 activity. This view is held by Schenk, who offers a number 

 of experimental results suggesting that increase in the tension 

 of a muscle so changes it that both the development and the 

 subsidence of the state of activity are hurried up ; the result 

 must be that the culminating effort due to active contractile 

 stress occurs sooner than it would otherwise do, since it is 

 both accelerated in onset and cut short or inhibited as 

 regards duration. In other words, Schenk regards a 

 mechanical pull as capable of stimulating the functional 

 capacity of the tissue both for passing into the active and 

 for returning to the passive or resting state. This view 

 involves issues of a comprehensive kind ; one of which is 

 the assumption of two separate excitatory processes, one 

 that of activity the other that of subsidence, whose presence 

 annuls or inhibits the former. It would be unprofitable to 

 review at length in the present article the arguments for and 

 against the acceptance of such an enlargement of our con- 

 ception of excitatory phenomena. The absence of such a 

 review may be further excused on the ground that Kaiser's 

 interpretation of the discrepancy is of an entirely different 

 nature. He regards the contractile stress in the muscle 

 as the same, however, recorded ; hence, as the muscular 

 event is in his opinion unaltered, the discrepancy must be 

 due to what may be termed the personal bias of one or 

 both of the historians. Does the isotonic curve faithfully 

 indicate the development and subsidence of the contractile 

 stress evoked in muscle by a single stimulus ? To ascertain 

 this he has carried out a number of extremely ingenious 

 experiments, the most convincing of which consist in the 

 production of so-called " arrest " curves. These are 



