1895.] On the Nature of Muscular Contraction. 415 



stance of the fibre is the seat of this chemical attraction, seems to me 

 difficult to understand, even if we assume as I believe we must do 

 that the number of the chemically active molecules is, even in the 

 smallest visible particle, so large that the distances which separate 

 them from each other and from the passively moving molecules lying 

 between them, fall within the limits in which molecular mechanical 

 influence can be exercised. 



The adherents of the chemio- dynamic hypothesis have not as yet 

 answered this objection. And since they can give but an unsatisfactory 

 account or no account at all of many other facts (I will refer to some of 

 these facts further on), we may be allowed to cast about for some 

 other explanation. 



The Electro dynamic Hypothesis. Since Gralvani's discoveries the 

 electric phenomena of the mtiscles have frequently been suspected 

 to contain the solution of our problem. And indeed, it is not so very 

 difficult to mention a series of facts which seem to bear out the 

 suggestion that the mechanical work done by the muscle may be 

 created from chemical energy through the medium of electric forces. 

 There is, in the first place, the fact that muscles, when in action, 

 produce regular electric effects. These effects are indeed the first 

 phenomena we can observe after the stimulation. They seem to begin 

 at the very moment of stimulation, shortly before the contraction ; 

 hence they might in so far be the cause of the mechanical process. 



Moreover, the value of the electromotive force, as du Bois-B/eymond 

 proved, is very high, and in the active particles is probably much 

 higher than the force of the currents we can derive from the surface 

 of the muscle. 



Add to this that the economic coefficient of the muscle may attain, 

 just as in the case of electric motors, a considerable proportion. As 

 much as 25 per cent, and more of the potential energy which has been 

 consumed may be transformed into mechanical work. 



However, there are weighty objections to this hypothesis also. In 

 the first place, there is the fact that these very same electromotive 

 forces, of equal intensity and direction, appear, under the same influ- 

 ences, not only in the muscles, but also in nerves, glands, and other 

 organs, which do not possess the least contractility. Then there is the 

 important discovery of Biedermann, that the contractility of muscles 

 may be completely neutralized by water or ether vapour, without 

 doing any perceptible harm to the electromotor phenomena. 



In the same way the development of the electric organs supplies us 

 with important proofs of the independence of the electric and the 

 mechanical processes. In most cases these organs are developed out 

 of striped muscular fibres. Now, in this process of development, 

 contractility is gradually lost, whereas the power of producing 

 electrical effects attains a yet higher degree of perfection. 



