390 ELECTRO-PHYSIOLOGY CHAP. 



From all this we may surely conclude in favour of the greater 

 simplicity of Hermann's alteration theory, the more so since, as we 

 shall see in the sequel, it brings under the same comprehensive 

 point of view those electromotive reactions in living tissues (gland 

 currents and vegetable currents), which have hitherto defied the 

 molecular theory. Finally, it is elevated above the rank of an 

 arbitrary hypothesis adjusted to the facts, by a series of experi- 

 mental researches, which leave no doubt as to the justice of its 

 fundamental conception. 



In addition to all the evidence above quoted, re " rest current " 

 and action current in the muscle (in respect of which the alteration 

 theory is luminous), a few data remain, which are best subjoined 

 in this connection. Foremost among these is the electromotive 

 reaction of the so-called idio-muscular contraction. We know that 

 in moribund muscle, especially in warm-blooded animals, conduc- 

 tivity disappears much earlier than excitability. The contractile 

 substance, as Funke expresses it, acquires more and more the 

 properties of a viscous mass, which tends to retain the local 

 impression instead of propagating it. Eventually, with localised 

 excitation, a merely local contraction results in the fibres, and is 

 usually persistent. Hence, as it were, a fixed wave of contraction 

 arises, extending over a greater or lesser section of the fibres. 

 The local persistent contraction must, however, correspond with 

 localised persistent excitation, and this again induces negativity 

 towards normal points of fibres. As early as 1857, i.e. ten years 

 before the formulation of the alteration theory, Czermak gave 

 proof that when the prepared nerve of a frog falls on a muscle 

 with an idio-muscular swelling, so as to bridge the latter and a 

 normal longitudinal point, a twitch ensues, thus demonstrating a 

 P.D. between the swelling on the one hand and the uninjured 

 surface on the other. Later investigations of Kiihne and Harless 

 prove that the swelling is invariably negative towards all other 

 points of fibre. 



We have observed repeatedly (Biedermann, 16) that negative 

 zones may be present also in the continuity of the frog's sartorius. 

 These are due to partial persistent contraction of the otherwise 

 uninjured muscle, and sometimes give rise to very powerful 

 currents. It is obvious that this may simulate the effect of a 

 pafelectronomic layer of measurable dimensions (parelectronomic 

 tract) at the uninjured ends of the fibre, since it is conceivable in 



