220 SECONDARY ELECTROMOTIVE PHENOMENA IN 



gradual disappearance in the process of dying with the acidification, 

 which, according to Ranke, lowers the resistance of muscle 2-4 times 

 more than boiling temperature 1 . In agreement with this also is 

 the observation of Ranke that the connective tissues which do not 

 lose their internal polarisability by exposure to a boiling temperature 

 (Sect. 1 1) undergo through it no diminution of their resistance. On 

 the other hand, it is not clear why a boiling temperature is more 

 injurious to polarisability than death is, since the latter reduces the 

 resistance considerably more than boiling temperature ; and the 

 general question is whether such a small reduction in the resistance 

 of the interstitial fluid as occurs on boiling the muscle, is capable 

 of an action for which the conducting capacity of vinegar, ammonia, 

 sulphate of copper and zinc solution is insufficient in other porous 

 bodies, such as blotting-paper 2 . 



Ranke places nerves among the tissues, the resistance of which 

 undergoes no alteration through boiling heat or death ; this creates 

 further difficulties 3 . In analogy with the white matter of the brain, 

 it may be inferred that the nerve-trunks are rendered acid by a 

 boiling temperature 4 . This would explain the destruction of inter- 

 nal polarisability at a boiling temperature, were it possible to under- 

 stand why the resistance of boiled nerves does not diminish, and 

 why dying nerves which do not become acid, lose their polarisability 5 . 



There is still another consideration in opposition to the view that 

 negative polarisation of muscle and nerve is a simple physical occur- 

 rence like the internal polarisation of wood, leather, etc. The de- 

 pendence of this negative polarisation on current density and time 

 of closure agrees well at first sight with such a view. Negative 

 polarisation seems to increase at first to some extent proportion- 

 ally to the product of these variables. It then slowly approaches a 

 limit. This is exactly the behaviour to which we are accustomed 

 in polarisation-currents generally, and which is easily explained by 

 the nature of polarisation. In muscles, however, and if I may trust 

 my old observations, also in nerves, a maximum of negative polari- 

 sation makes its appearance with an increasing time of closure. 



1 Eegarding the acidification of boiled and dying electrical organs, see the Gesam- 

 melte Abhandlungen, vol. ii. p. 646 ; Untersuchungen am Zitteraal, p. 70. 



2 Tetanus; Eine physiologische Studie, Leipzig, 1865, pp. 35 ff. 



3 Gesammelte Abhandlungen, vol. i. pp. 25, 26; vol. ii. p. 190. 

 * Loc. cit. pp. 33, 38. 



5 Gscheidlen in Pfluger's Archiv, 1874, vol> vi "' P- I 7 I - Oddly enough, there 

 seem to be no experiments on the reaction of boiled nerve-trunks themselves. Comp. 

 Hermann in his Handbook, p. 1 39. 



