1265 
too small one’), but a careful study, showing the relation between 
the [Ca] degree and the vagus-irritability, has not come to our 
knowledge. For this reason we have tried to find this relation as 
it was also done with the surviving frog’s kidney *) and the haemolysis ®). 
The perfusions were done as follows: 
The abdominal wall, thorax wall, and clavicula of the frog (d') are carefully 
cut away, also the extremities are removed and the test object is nailed to a board. 
For a better survey the intestines may also be removed as far as the duodenum 
provided the mesogastrium is not injured. The canula is inserted into the a. coe- 
liaca; the a. mesenterica is tied tight. In this way stomach + liver and gall- 
bladder (art. hepatica) are perfused. The pressure may be regulated by the level 
of the liquid-reservoir and the orifice of the canula. 
Should it be desired to perfuse the whole of the intestines + portal circulation, 
than the a. mesenterica is not tied; liver (arterial and venous), wall of gall-bladder, 
stomach and intestines are then perfused. The proximal part of the v. abdominalis 
must be tied. 
The n. vagus is stimulated by inserting electrodes in the tubae Eustachii; this 
is done most easily, by hammering 2 copper nails through the tubae into the board. 
With this method of stimulation we always see (by very constant coils-distance) 
the vagus-effects on heart and stomach-intestines. 
The duration of each experiment was about 1'/, hours. 
We have now observed the influence of the Ca-ion-concentration 
in about 75 perfusions. Beforehand the irritability and the motility 
of the stomach-wall of the newly-killed not-perfused frog was deter- 
mined, which existed as much as possible under physiological conditions. 
Afterwards the perfusions took place with the following solutions: 
1. NaCl 0,6°/,. 
2. NaCl 0,6°/,, then NaCl 0,5°/,, NaHCO, 0,20°/,, CaCl,.6 aq. 
0,040°/,, KCl 0,020°/, Pr == + 8,6 *). 
3. NaCl 0,6°/, + KCl 0,02°/,. 
4. NaCl 0,6°/, + KCl 0,02 °/, + CaCl, .6aq. 0,005°/,, 0,010°/,, 
0,012°/,, 0,014°/, ete., 0,020°/,, 0,025°/, etc. 
5. NaCl 0,5°/,, NaHCO, 0,28°/,, CaCl,.6 aq. 0,040°/,, KCl 0,02°/,, 
Py varying considerably: from 8,6 to 7,2. 
6. NaCl 0,6°/,, CaCl,.6 aq 0,040°/,, KC10,02, Py=8,6, NaHCO, 
0,05°/,, 0,010°/,, 0,0015°/, etc. 
1) Josep E. MELTZER: Americ. Journ. o. Physiol. 29, 1, 1911. 
BENDA: Zeitschr. f. Biol. 63, 11, 1914. 
2) HAMBURGER u. BRINKMAN, l.c. 
3) BRINKMAN: l.c. 
4) Colorimetricai according to SORENSEN. 
