482 REPORTS ON THE STATE OF SCIENCE. 



I do not thiuk we Ctan profitably specialise these words in this way ; ^ but 

 if not we must have new words, for there can be little doubt that both 

 processes take part in the production of fatigue, and we must distinguish 

 between them and hold fast the two conceptions. 



The question then arises. What are the seats within the nervous 

 system of these two processes, 'Erschopfung'and 'Ermiidung'? Verworn's 

 view may perhaps claim the adherence of a larger number of physiologists 

 than any other. It is very simple. According to this view, the cell- 

 bodies, or ' ganglion cells,' are the seats, or at least the principal seats, of 

 both processes, and both result in a diminished katabolism and output of 

 energy by the cell-body. ' Erschopfung ' is thus, according to this view, 

 a strictly local process, affecting only the bodies of the nerve-cells involved 

 in any activity ; while ' Ermiidung ' is both local and general, because the 

 cell-body is liable to be poisoned not only by the waste products of its 

 own activity, but also by those of the metabolism of other nerve-cells and 

 of other tissues of all parts of the body, especially the muscular tissues ; 

 for these waste products, wherever formed, may pass into the blood and 

 lymph and so may reach the ' ganglion cells.' 



Now I venture to say that this picture of the nature of fatigue of the 

 nervous system is very much too simple ; the conceptions are, I contend, 

 true and useful, but inadequate to the explanation of the complex mani- 

 festations of fatigue which meet us as soon as we consider the organism 

 as a whole ; and they are inadequate also for the explanation of maiay of 

 the special and local manifestations of fatigue. 



The picture needs, it seems to me, to be complicated by two most 

 important additions. First, Verworn's scheme takes little or do account 

 of the resistances that the nervous energies have to overcome. Now if 

 with him we regard the cells as seats of explosive decompositions and the 

 nerve-fibres as freely conducting excitations, cither as purely physical pro- 

 cesses or, with more probability, as physico-chemical processes involving 

 metabolic changes similar to those that occur in the cell-bodies, then it 

 is obvious that there must be points or parts of the nervous tracts which 

 delimit functional units and groups of units ; else, instead of the orderly 

 sequence of nervous excitations which normally follow upon any stimula- 

 tion, the excitation would spread indefinitely throughout the nervous 

 system, soon producing inco-ordinate general activity and a rapidly 

 ensuing general exhaustion ; in the way the results of which we see in 

 the convulsions of strychnine poisoning. 



Now the question. Where, in what structures, do these resistanzen reside? 

 is one of secondary importance perhaps, so long as we recognise their nature 

 and function. Still, it is a question of some interest. In a recent paper 

 Verworn recognises the existence of resistances and assigns them, like all 

 the other peculiarities of the central nervous system, to the cell-bodies.''' 

 To that view serious objections may be raised. To mention only one, 

 it is difficult to suppose that the cell-bodies are the seats both of explosive 

 decompositions which liberate energy and also of the resistances which 

 delimit the paths by which the excitation spreads towards the different 



' Because we Deed the word ' fatigue ' to denote the state of diminished efficiency 

 of the organism as a whole commonly produced by these two processes in con- 

 junction, and we need the word ' exhaustion ' to denote the extreme degrees of the 

 state resulting from excess of metabolism over anabolism. 



- ' Die Cellularphysiologische Grundlage des Gedachtnisses,' Zeitsch.f. Allgenwine 

 Phijsuilogie, Bd. vi. 



