THOMPSON YATES LABORATORIES REPORT 
EXPERIMENT IX 
Sciatic Nerve of Cat 
Piece of Nerve 5 centimetres long. Experimental solution used : '25 per cent. NaOH. 
First Nerve removed at once 
Second Nerve 
removed in one hour 
Potential difference of the nerve upon removal 
20' I X 
10-3 D. 
io - 6 x 10— 3 D. 
(5) After 5 minutes in -25 per cent. NaOH ... 
9-0 
77 
8-2 
(10) Another „ ,, ,, 
3'4 
77 
5' 2 
(15) » j» » » 
21 
77 
(20) „ ,, ... 
i-6 
77 
i-8 
In this experiment the same fact is seen elicited by a solution which has the 
typical effect of a concentrated solution. Nor is this revelation of the still pristine 
vigour of the nerve limited to the action of acids and alkalies, it may be observed 
more or less completely in the case of the action of any solution of electrolytes. 
A reference to the data of Experiment VI will show the same influence at work, as 
revealed (at a longer interval after death) by the. solution of a neutral salt (KC1). 
In the next section the influence of this factor is seen in the data obtained from every 
solution of electrolytes used : the preliminary difference is there seen as the result of 
a stay of only five minutes longer in the body, and its removal is seen as a conse- 
quence of immersion in many different solutions. 
In all the experiments previously quoted, the experimental solutions into which 
the nerve was placed have been of the temperature of the room. In the succeeding 
section care has been taken that in every case the solution used should be at the same 
temperature, i8°C, and that this should be maintained constant. In an examination 
of a process presumably dependent upon a diffusion process, the precaution of main- 
taining a constant temperature is an obvious necessity, the rate of diffusion being 
notably influenced by temperature. The choice of a standard temperature is more 
or less a matter of convenience, and the most convenient, from the point of view of 
physical measurements, is the temperature chosen. This standard temperature was 
not, however, chosen at once, since in the case of mammalian nerve certain other con- 
siderations are of value. The nerve removed rapidly from the animal is already at a 
temperature of 38° C. approximately, therefore scruples which dictate a study of, what 
is called, nerve in a normal condition point to the selection of this temperature for 
the examination of the nerve. One scruple of this kind, more definite than the 
remainder, is strongly in favour of such a course, namely, that which is affected by 
the condition of the myelin sheath. 
