XXV 
ON IONS WHICH ARE CAPABLE OF CALLING FORTH 
RHYTHMICAL CONTRACTIONS IN SKELETAL 
MUSCLE! 
1. In 1881 Biedermann published a remarkable observa- 
tion “On Rhythmical Contractions Brought about in Striated 
Muscle through Chemical Stimulation.” The observation 
consists, according to his description, in the following: 
The sartorius of a frog, previously poisoned with curare, is 
carefully removed from the body, if possible at a low temperature 
(0 to 10° C.). If now the muscle preparation fastened vertically 
into a muscle clamp, and weighted by its femoral stump, is dipped 
into a 0.6 per cent. sodium-chloride solution ... . containing 
some ordinary alkaline, crystallized sodium phosphate, besides a 
small amount of sodium carbonate (in the liter of distilled water 
were contained 5 g. NaCl, 2 g.Na,HPO,, and 0.4 to 0.5 g. Na,COs), 
which must be kept at a low temperature (3 to 10°C.), one observes 
as a rule, after a longer or shorter period of rest, that the immersed 
muscle begins to beat rhythmically. 
The twitchings vary in intensity. At times we have to do 
with a mere tremor; at times, however, powerful beats and 
contortions of the muscle occur; sometimes only individual 
fibers are active; sometimes the whole muscle is involved. 
Finally, the process may be limited to certain portions of 
the muscle; at other times the whole muscle may be involved. 
At low temperatures these phenomena may continue for 
days. 
Biedermann recognizes the importance of this observa- 
tion for the decision of the question whether the heart muscle 
is of itself capable of rhythmical activity without the inter- 
vention of the ganglion cells. 
1 Festschrift fiir Professor Fick (Braunschweig, 1899), p. 101. 
2 Sitzungsberichte der Wiener Akademie, Vol. LXXXII, Part III (1880). 
518 
Digitized by Microsoft® 
