1264 
test-organ we selected the perfused, surviving frog’s stomach, on 
which we can easily study the influence of the N. vagus on the 
motility. . 
The general significance of the Ca-ions for the irritability of the 
cerebro-spinal and the autonomic, central and peripheric nervous 
system has been known for some time. 
Locke’) demonstrated that the Ca-ion is necessary for conducting 
the stimulus from a nerve to a voluntary muscle. OvERTON ’) proved 
that it was equally indispensable for preserving the synapsis between 
nerve-ending and ganglion-cell. 
Busquet and Pacuon*) showed that the irritability of the N. vagus, 
which soon disappears on perfusing the heart with a pure NaCl- 
solution (Howerr)®), returns by adding small quantities of Ca. They 
further found, as did also SaBBATAN1®) by testing many calcium-salts 
of widely differing degree of dissociation, that we are definitely 
concerned with an ion-influence and that undissociated Ca-salts were 
of no importance for the balancing effect. 
It is the concurring opinion of all investigators that the explana- 
tion of this Ca-ion effect must be sought again in the influence on 
the synapsis-colloids which is antagonistic to Na and K. From the 
above-mentioned experiments of NeEuscHiosz°) as well as from said 
physiological experiments °) it appeared also that this | Ca” ] must have 
a very special constant value, and that slight variations of the physi- 
ological [Ca”] may be of great influence. A total absence of Ca™- 
ions will never occur in vivo, but especially these slight fluctuations 
of |Ca”| are important under. physiological conditions. 
It is true that in the literature of the subject there are indications 
to be found that a too large quantity of Ca is as detrimental as a 
1) Locke: Zentralblatt f. Physiologie 8, 166, 1894. See farther 
CusHING: American Journal of Physiology, 6, 77, 1902; 
Mines: Journal of Physiology, 42, 251, 1911. 
2) OvERTON: Pfliiger’s Archiv. 105, 261 and 280, 1904. 
3) Busqurr et PacHon: Journal de Physiologie et de Pathologie Gén. 11, 807 
and 851, 1909. 
Mines l.c.; Loewr: Archiv. f. Exp. Pathol. 70, 343, 1912. 
HAGGAN and ORMOND: Amerc. Journ. o. Physiol. 30, 105, 1912. 
CAZZOLA: Archivio di Fisiol. 11, 88, 1913. 
*) HoweLL: Americ. Journ. o. Physiol. 15, 280, 1906. 
6) SABBATANI: C. r. Soc. Biol. 54, 716, 1902. 
6} NEUSCHLOSZ: le. 
7) HAMBURGER and BRINKMAN: l.c. 
