52 David H. Dolley, 



* 



waste products, such as sarcolactic acid and mono-potassium phosphate, 

 are by no means highly efficient in producing anatomical depression. 

 A single large dose gave the slightest possible change, if any change 

 at all were morphologically perceptible. Eepeated doses acting for 

 some time are necessary. Severe depression in the case of other 

 toxic factors came only with an obvious swamping of the organism. 

 On the contrary, a highly specialized cell is most labile and sensitive 

 to the effect of work. The results obtained by working dogs in the 

 treadmill (Table 1, 1909c) indicate that and, further, exhaustion 

 proceeds very slowly to recovery (1911a). It is this contrast which 

 strengthens the impression that the waste products are a minor factor. 

 "Without further elaboration, the changes from excitation are primordial 

 not only on a rational basis but are given the first place by experi- 

 mental analysis. 



It now becomes necessary to discuss the error to which the 

 neglect of Verworn's distinction between exhaustion of excitation and 

 fatigue of depression, with the consequent undue prominence given to 

 the latter, has led. 



While attention to this distinction would have minimized the 

 error, yet in a degree it cannot be regarded as an avoidable induction, 

 for lack of knowledge of certain properties of the nerve cell reaction 

 in its slow advance has contributed to its development. The error 

 in question lies in predicating for the nerve cell an inexhaustibility 

 which is not sufficiently limited to a relative inexhaustibility in respect 

 to other parts. The undue emphasis which this relative inexhausti- 

 bility has received is pregnant with superficial, even harmful deductions. 

 So far from giving it a place, any vestige of an idea that there is 

 anything approaching an actual inexhaustibility will be combatted 

 under the heading 



The Exhaustibility of the Nerve Cell. 



"While for the most part this predicated inexhaustibility is plainly 



specified as one relative to the other elements in the neuro-muscular 



mechanism, j^et the writer takes the ground that even speculation on 



an extension of it has had a dangerous influence. Its outcropping? 



