1244 



Also ill similar experiments on the genese of' tetanus, no essential 

 differences pointing in one special direction between normal fi'Og 

 muscles and those deprived of their sympathetic innervation, could 

 be observed. 



We come therefore to the conclusion that until now not a single 

 experimental fact exists, pointing clearly to a direct connection 

 between the mechanical tonus of the- muscles in the sense of 

 Brondgekst, and the sympathetic nervous system. As regards to the 

 initial hypotouus occurring in my experiments, the solution of this 

 question ought to be given by further experiments. Special attention 

 ought to be drawn to the fact already mentioned, that this hypo- 

 tonus in the experiments of v. Brücke disappears already some days 

 after the extirpation of the sympathetic. At all events the commu- 

 nication of VON Brücke has cousideral)ly weakened de Boer's theory. 

 This as regards the mechanical muscle tonus. 



1 have now to refer briefly to the chemical muscle tonus. 

 G. Mansfeld and A. LuKacs *) communicated experimental facts from 

 which they deiive the existence of a so-called chemical musclelonns, 

 by which term is expressed the view that striped muscles would 

 have a certain amount of metabolisni, also when they are at rest. 

 This metabolism would be under the influence of the sympathetic 

 nervous system. A\ first 1 thought '') that the experiments, published 

 by these investigators, were not convincing, and lately 1 briefly 

 explained'') my former objections against them. 



Since 1 have come to the conclusion that the criticism given by me 

 is not sound, I recall it. All the same, the authors might have based their 

 result even better, if they had made direct gasanalyses of the blood 

 streaming to and from the muscles concerned. If the result of these 

 analyses should confirm their former results, only then there could 

 be no more doubt with regard to the accurateness of their result*). 



The objection might yet always be raised against the respiratory 

 analyses executed on the whole animal, that their result might 

 be dependent on the fact, that by the extreme vaso-dilatation in 

 the hind part of the l)ody of their animals, too little blood 

 remained in the fore part of the body, to preserve a fit exchange of 

 gas in the muscles there, so that the respiratory metabolism might 



') I.e. 



2) Pflüger's Archiv. Bd. 166, 1916, p. 152. 



') Archives Néerlandais de Physiologie, tome II, 1918, p. 177. 



*) A similar method as the one used by Langley and Itagaki for their expe- 

 riments on the oxygen use of denervated muscle, came into consideration (Journal 

 of Physiology, 51, 1917. p. 202). 



