362 PHYSIOLOGICAL DEVELOPMENT. 



case the water should become visible between the substance 

 of the fibre and its sarcolemma or sheath, it may be rejoined 

 that this is not necessary it may be deposited interstitially. 

 Possibly the striated structure is one that facilitates its 

 exudation and subsequent re-absorption; and to this may be 

 due the superiority of striated muscle in rapidity of contrac- 

 tion. Granting the speculative character of this 

 interpretation, let us see how far it agrees with the facts. If 

 the actions are as here supposed, the contracted or more inte- 

 grated state of the muscular colloid will be that which it 

 tends continually to assume that into which it has an in- 

 creasing aptitude to pass when artificial paralysis has been 

 produced, as shown by Dr. Norris that into which it lapses 

 completely in rigor mortis. The sensible motion generated 

 by the contraction can arise only from the transformation 

 of insensible motion. This insensible motion suddenly 

 yielded up by a contracting mass, implies the fall of its 

 component molecules into more stable arrangements. And 

 there can be no such fall unless the previous arrangement is 

 unstable. From this point of view, too, it is possible 

 to see how the hydro-carbons and carbo-hydrates consumed 

 in muscular action, may produce their effects. For these 

 non-nitrogenous elements of food, when consumed in the 

 tissues, give out large amounts of molecular motion. They 

 do this in presence of the muscular colloids which have lost 

 molecular motion during their fall in the stable or contracted 

 state. From the molecular motion they give out, may be 

 restored the molecular motion lost by the contracted colloids ; 

 and these contracted colloids may thus have their molecules 

 raised to that unstable state from which, again falling, they 

 can again generate mechanical motion. 



This conception of the nature and mode of action of mus- 

 cle, while it is suggested by known properties of colloidal 

 matter and conforms to the recent conclusions of organic 

 chemistry and molecular physics, establishes a comprehensible 

 relation between the vital actions of the lower and the higher 



