TRANSACTIONS OF SECTION D. 611 



terminolog-y of Ntigeli and Pfefferas descriptive of the mechanism of its contraction. 

 Muscular protoplasm difl'ers from those kinds of living matter to which I have 

 applied the term ' polyergic,' in possessing a molecular structure comparable with 

 that of a crystal in this respect, that each portion of the apparently homogeneous 

 and transparent material of which it consists resembles every other. 



With this ultra-microscopical structure, its structure as investigated by the 

 microscope may be correlated, the central fact being that, just as a muscular fibre 

 can be divided into cylinders by cross sections, so each such cylinder is made up 

 of an indefinite number of inconceivably minute cylindrical i)art8, each of which 

 is an epitome of the whole. These, Engelmann, following Pfefier, calls ino-tagmata. 

 So long as life lasts each minute phalanx has the power of keeping its axis parallel 

 with those of its neighbours, and of so acting within its own sphere as to produce, 

 whenever it is awakened from the state of rest to that of activity, a fluxion from 

 poles to equator. In other words, muscle, like plant protoplasm, consists of a 

 stable framework of living catalysing substance, which governs the mechanical and 

 chemical changes which occur in the interstitial catalysable material, with this 

 diflerence, that here the ultra-microscopical structure resembles that of a uniaxial 

 crystal, whereas in plant protoplasm there may be no evidence of such arrange- 

 ment.' 



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

 change of form which, if allowed, a muscle undergoes when stimulated, has its 

 seat not in the system of tagmata, 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 the electrical state of the living substance. Let us now see how far the 

 scheme will help us to an understanding of this marvellous concomitance of 

 chemical, electrical, and mechanical change. 



It is not necessary to prove to you that the discharge of carbon dioxide 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 each 

 tagma an accumulation of oxygen and oxidisable material, and that con- 

 comitantly with or antecedently to the migration of liquid from pole to equator, 

 these must come into encounter. Let us for a moment suppose that a soluble 

 carbohydrate is the catalysable material, that this is accumulated equatorially, 

 and oxygen at the poles, and consequently that between equator and poles water 

 and carbon dioxide, the only products of the explosion, are set free. That the 

 process is really of this nature is the conclusion to which an elaborate study of the 

 electrical phenomena which accompany it has led one of the most eminent 

 physiologists of the present time. Professor Bernstein.'- 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 Pfliiger and with the scheme of Engelmann, 

 ■with this addition, that each ino-tagma is electrically polarised when in a state of 

 rest, depolarised 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 

 fibre, and consequently have their positive sides exposed. In this amended 

 form, the theory admits of being harmonised with the fundameutel facts of 

 muscle-electricity, namely, that cut surfaces are negative to sound surfaces, and 

 excited parts to inactive, provided that the direction of the hypothetical polarisa- 

 tion is from equator to pole, i.e. that in the resting state the poles of each tagraa 

 are charged with negative ions, the equators with positive; and consequently 

 that the direction of the discharge in the catalyte at the moment that the 

 polarisation disappears is from pole to equator. 



' Briicke, VorUmngen, 2ud edition, vol. ii., p. 497. 



* Bernstein, ' Neue Theorie der Erregungsvorgange and electrischen Erscheinungen 

 an den Nerven- und Muskelfasern,' Untersuchungen am dem, Physiologisch^n Institut, 

 Ualle, 1888. 



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