Conductivity in Nerve Trunks. 
39 
Ten experiments were made, nine of which gave the following 
uniform results which we shall state very briefly. 
Primary action of calcium chloride. — In every experiment a time 
came when the conductivity of the nerve trunk became finally 
abolished ; stimulation of the lumbar plexus gave no reaction, while 
stimulation of the distal part of the sciatic nerve brought out a 
good response. This, however, occurred only after prolonged 
bathing. Ninety minutes was the shortest period; in some cases 
it took 150 minutes and longer before all response from the lumbar 
plexus disappeared. 
This result bears out our original conclusion. In our former 
experiments the indirect irritability disappeared after a few 
minutes exposure to the action of the calcium chloride. This 
could not have been due to the action of the calcium solution 
upon the nerve trunk since calcium is able to produce abolition 
of conductivity only after hours of bathing. 
Reversible; restored by sodium chloride. — In every experiment 
the vanished conductivity came back after replacing the calcium 
solution by an M/10 solution of sodium chloride. The conduc- 
tivity returned in a comparatively short time, probably in less 
than 15 minutes. After recovery, the lumbar plexus responded in 
a manner similar to that of the distal part of the sciatic nerve, 
which after several hours of exposure to the abnormal surroundings 
usually lost somewhat of its original irritability. 
Primary action of sodium chloride. — It has been established 
already by Locke, and by Overton, that physiological salt solution 
does not affect the conductivity of the nerve trunk. Our experi- 
ments simply confirm these statements. After many hours of 
bathing of the nerve in an M/10 sodium chloride solution the 
lumbar plexus lost indeed some of its original irritability; but the 
loss was not greater than that of the distal section of the sciatic 
nerve which was kept covered throughout the experiment with 
cotton saturated in Ringer. We ought to add that the tempera- 
ture of the laboratory during the period in which the experiments 
were carried out (November) was by no means low. 
