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POSITIVE ELECTRICAL VARIATION IN ISOLATED NERVE. 
By W. a. Jolly. 
(Received May 15, 1912.) 
(With Five Text-figures.) 
Tlie electrical changes which occur in living tissue form a valuable part 
of our data in the investigation of vital processes. In living nerve the 
difficulty of demonstrating any change of form, chemical change or evolution 
of heat, or distinct histological modification accompanying activity renders 
the study of the electrical changes especially important. 
These changes in nerve are various. Some are clearly dependent on 
its physical properties of electrolytic conduction and polarisation, others 
must be ascribed to its special activities as living tissue. Wide generalisa- 
tions regarding the anabolism and katabolism of all living tissues are to a 
considerable extent based upon the changes of opposite sign which occur 
in nerve. 
The literature on the subject is very extensive, and many different 
instruments and methods of investigation have been employed. 
It is no easy matter to correlate the results obtained by different 
observers in this branch of research and to interpret them in the light of 
later work. 
The following contribution to the subject forms a sequel to work 
undertaken in the Physiological Laboratory of Edinburgh University, 
the results of which were communicated to the Physiological Society of 
England. 
When a nerve isolated from the body is stimulated by the faradic 
current it was shown by Hering" that at the close of the stimulation an 
electrical variation appears which deflects a galvanometer in the same 
direction as the demarcation current of the nerve, that is to say, there is a 
positive variation. 
* Beitr. z. allgem. Muskel u. Nervenphysiologie. 15 Mitt. Sitzungsber. d. Wiener 
Akad. Bd. 89. 3 Abt. 1884. 
