460 
Number 17. 28—1—16 t= 13° Rana esculenta, experiment with the sinus 
venosus; both venae cavae sup. and one of the aortas cut through, the other one 
tied off. 
After some other fluids : 
2.40. RinGer being led through, number of contractions per min. : 22. 
2.44, RINGER without CaCl,. Number of contractions per minute: after 5’: 24: 
after 10’: 24; after 15’: 22; after 20’: 22; after 25’ : 22; after 30’ : 23; after 45’ : 21; 
after 50’: 22; after 55’:21; after 60’: 21, 
3.46. led through: Rincer. Frequency per minute after 5’: 22; after 10’; 22; 
after 15’. 29: 
As regards deviation and tonus the former regularly decreased to 
O0: the latter did not always manifest itself in the curves, but 
likewise tends to a decrease. 
Hence the sinus and ventricle automatism differ considerably 
regards frequency. The sinus is retarded by an addition of CaCl, to 
the physiological doses, the ventricle is stimulated into greater 
frequency, likewise retarded, however, in higher concentrations. 
The difference may perhaps after all be reduced to a difference in 
degree, for starting from Rinxenr’s solution without CaCl, I observed 
when I passed on to a weak concentration, a more rapid rhythm 
also of the sinus, but at higher concentration a smaller frequency 
again. The difference is that the maximum frequency for the sinus 
lies below the physiological concentration of CaCl, and that for the 
ventricle above it. This makes it clear why they may behave 
differently at or near the usual concentration. 
RCE 
The diagrams II] and IV relate to the frequency when the quan- 
tities of KCl are changed. In III we had 0.01 °/, of CaCl, 6 aq 
and in IV 0.01 ®, CaCl, without water of crystallization. See also 
he: 
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ANIL SMAI 
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nara 
Fig 3. Retardation of the rhythm by withdrawal of KCl. At K 
Ringer flowed through. At U (70 after K° the last quanti 
tity of KCl bad been withdrawn for 40’. Time marked in 
half minutes. 
