ELEMEKTAKY I'KOBI.HMS IN i'Jn SK)LO( ; Y. 429 



substance, wbicli governs the mecbauical and cbeniical changes that 

 occur in the interstitial catalysable material, with this difference, that 

 here the nltra-niicroscopical structure resembles that of a uniaxial 

 crystal, whereas in plant ijrotoplasin there may be no evidence of such 

 arrangement.* 



According to this scheme of muscular structure, the contraction, i. c, 

 the change of form which, if allowed, a muscle undergoes when stimu- 

 lated, has its seat not in the tagma, but in the interstitial material 

 which surrounds it, and consists in the migration of that labile material 

 from pole to equator, this being synchronous with explosive oxidation, 

 sudden disengagement of heat, and change in ?lectrical state of the 

 living substance. Let us now see hov," far tlje scheme will help us to 

 an understanding of this marvellous cuncomitance-of chemical, elec- 

 trical, and mechanical change, 



It is not necessary to prove to you that the discharge of carbon diox- 

 ide and the production of heat which we know to be associated with 

 that awakening of a muscle to activity which we call stimulation are 

 indices of oxidation. If we take this fact in connection with the view 

 that has just been given of the mechanism of contraction, it is obvious 

 that there must be in the sphere of tagma an accumulation of oxygen 

 and oxidizable materiiil, and that concomitantly with or autecedently 

 to the migration of liquid fron) pole to equator these must come into 

 encounter. Let us for a moment suppose that a soluble carbo-hydrate 

 is the catalysable material, that this is accumulate<l equatorially, and 

 oxyg'Mi at the poles, and consequently that between ecpiator and poles 

 water and carbon dioxide, the only products of the explosion, are set 

 free. That the process is really of this juiture is the conclusion to which 

 an elaborate htudy of the electrical phenomena which accompany it, has 

 led one of the most eminent i)hysiologists of the present time, Professor 

 Bernstein. t To this I wish for a moment to ask your attention. 



Professor Bernstein's view of the molecular structure of muscular 

 protoplasm is in entire accordance with the theory of Ptliiger and witb 

 the scheme of Engeimann, with this addition, that each ino-tagma is 

 electrically polarized when in a stateof rest, dejxdarized at the moment 

 of excitation or stimulation, and that the axes of the tagmata are so 

 directed that they are always parallel to the surface of the fiber, and 

 consequently have their positive sides exposed. In this amended form 

 the tbeory admits of being harmonized with the fundamental facts of 

 muvscle-electricity, namely, that cut surfaces are negative to sound sur- 

 faces, and excited parts to inactive, i)rovided that the direction of the 

 hypothetical polarization is from e<iuator to pole, i. c, that in the rest- 

 ing state the poles of each tagma are charged with negative ions, the 



"Briicke, VorleHungen, ^d edition, vol. ii, p. 41)7. 



t Bernstein, "NeueThcorie dor Eriegnngsvor^ango und eiectriacheu Er.slioinungeu 

 an den Nerven- und Mnskel- Casern," ['iitcrsiichinKjcn o us don I'liysiolixjischcn Itmlitut, 

 Ilulle, 1888. 



