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1. The influence of a pure NaCt-solution on the motility and 
the irritability of the vagus of the muscular-stomachwall. 
When observing the stomach of a newly-killed frog, one often 
notices spontaneous local contractions or peristaltic waves in both 
directions. Stimulation of the vagus, brought about in the way 
described above, causes strong peristaltic movements, especially in 
the pyloric part; at the same time one can observe a frequent 
lengthwise contraction. The stimnlation has a rather long after- 
effect (5 minutes). It was constantly found that the minimum degree 
of effective stimulation was with a coils-distance of 7 to 8 ¢.m. 
[f the stomach is perfused with a 0.6 °/, NaCl solution Py = 8.6), 
we see that the spontaneous peristalsis has disappeared after 5 to 10 
minutes and that the stomach has become quite limp; the mechanical 
irritability has completely disappeared. 
The vagus-irritability is as follows: before the perfusion a vagus- 
effect is observed with a coil-distance of 7 to 8 e.m.; after a 5 
minutes perfusion a distance of 5 c.m.; after 10 minutes a distance 
of 4 to 3 em.; after 15 to 20 minutes even the strongest stimulation 
of the vagus takes no effect. 
This disappearance of the vagus-irritability 1s reversible. If, after 
half an hour’s perfusion with the pure NaCl solution, the liquid is 
replaced by a well-equilibrated salt-solution (NaCl 0.5 °/,, NaHCO, 
0.28 °/,, CaCl, 6 aq 0.040 °/,, KCl 0.020 °/,, Pa == 8.6) spontaneous 
contractions are again observed after five minutes; after 10 minutes 
vagus-effect occurs at 10 em. coil-distance, after 25 minutes vagus- 
effect can be observed clearly at a coil-distance of 7 cm. 
So it is clear that after half an hour’s perfusion with a pure 
NaCl solution, the harmful action is still perfectly reversible. 
2. The influence of NaCl + KCl. 
Now we have tried to find out which ions of the physiological 
solution in this respect caused the balancing effect. It soon appeared 
that the addition of K-ions, to which one has to assign such an 
important effect in heart-perfusion, have no effect of importance here. 
A concentration of K-ions which can cause the return of the vagus- 
irritability cannot be found. 
3. The influence of NaCl + KCl+ Call. 6 aq. 
The vagus-influence may be re-established by the addition of a 
certain calcium-concentration to the (in itself insufficient) system of 
