THE INJURY CURRENT OE NERVE 
composition and physical conditions. ' Vital ' phenomena, not otherwise known to 
exist, are practically created to explain an interesting physical phenomenon ; and are 
suitably arranged in the course of the nerve fibre in a manner which is not open to 
corroboration. 
To Du Bois Reymond such an acceptance would have involved not only the 
abandonment of a particular theory, but also the relegation of his whole subject to 
the regions of empirical symbolism. It is not surprising, therefore, that immediately 
the theory was promulgated he entered the field against it. 1 
The extent of the controversy is well known. The experimental data collected 
during its prosecution will, doubtless, be remembered, when the words which hurled 
them into the possession of contemporary science have long been forgotten ; but 
Du Bois Reymond will then have been reinstated as the founder of a scientific 
method of physiological research, and will thus have a more honoured remembrance 
than as the discoverer of a fact or a series of facts, or as the defender of a perhaps 
too confidently-held position. In the meantime the indirect outcome of the con- 
troversy and of its lessons has been a philosophy, which sees in comparative 
' negativity ' a long sought-for rule, by which to measure accurately the relative 
intensity of life in two contrasted situations. 1 In repose positive, in activity negative, 
only given a standard of candle power the value of any vital spark could immediately 
be assessed by the galvanometer. 
In 1877, Hermann 5 published experimental data, which very largely moulded 
the general opinion as expressed in contemporary and in subsequent text-books. 
These data, obtained by the use of his ' fall rheotome,' proved that the current of 
injury did not traverse the galvanometer circuit in fully developed strength for a 
short interval ("0025") after the occurrence of the injury. 
The fact was advanced as conclusive evidence against all ' pre-existence ' theories ; 
so that Du Bois Reymond's and Grunhagen's and every similar point of view must 
be abandoned. The conclusion was practically accepted, and has been followed by 
consequences of importance. 
To regard the injury current as possibly the outcome of pre-existing conditions 
is to regard it as a phenomenon of primary interest, as, in fact, a possible key to the 
desired knowledge of the physical structure of the nerve, and, therefore, to the know- 
ledge of the possibilities of the meaning of its physical change during function. 
The fall rheotome experiments temporarily removed any general confidence 
which had been maintained in such a possibility, and, as a consequence, deposed the 
phenomenon to a rank of secondary importance. 
The delay measured by means of the fall rheotome is, however, by no means 
conclusive evidence of a time spent in the initiation of chemical or of vital change. 
1. Du Bois Reymond, Monatsberhhte d. Konigl. Akad. d. Win., Berlin, 18(17, p. 597 ; reprinted in Du Bois 
Reymond's Gosamtnt Abhandl., II, p. 319. 
2. E. Hering, Lotos, Prague, 1888 ; translated 'Brain, 1897, p. 2}2.' 
3. Hermann. Pfiugers, Archi-v., XV., p. 191. 1877. Experiments upon muscle. 
