896 REPORT—1899. 
have placed their conducting fibres. After this lesion the auricles and ventricles 
continued to beat in coordination as before. After cutting most of the apex 
away from the base, but still leaving a large number of connecting fibres, the apex 
ceased to beat while the base continued to pulsate. 
If now the septum ventriculorum of the base was incised in several places, the 
base either ceased to beat entirely or the bases of the two ventricles pulsated 
incoordinately. 
These facts cannot be explained by the theory of the myogene nature of the 
heart pulsation. 
Also, we cannot understand, however slow the conduction ina muscle may be, 
how the pause between the contraction of the auricles and the ventricles can be 
thus explained. 
It is also impossible to explain by the myogene theory the fibrillation of the dog’s 
heart after a mechanical lesion of a very small region in the septum ventriculorum, 
where we must place the vasomotor centre of the coronary arteries. 
3. Concerning Fibrillation and Pulsation of the Dog’s Heart. By Dr. 
F. C. Buscu. [from the Physiological Institute of the University of 
Bern.] 
Dr. Busch observed the excised dog’s heart, which was still beating weakly 
after being cut out, to pulsate when perfused through the large descending branch 
of the left coronary artery with a mixture of equal parts of defibrinated dog’s 
blood and 0°6 per cent. salt solution at 38°C. 
The contractions were at first irrerular and weak, but became regular, stronger, 
and more frequent as the perfusion continued. 
When the muscle was tetanised, it fibrillated only during the excitation. 
This result agrees with observations made by Porter. 
In other cases we found that the part of the dog’s heart which was perfused 
with a mixture of equal parts of defibrinated calves’ blood and 0-6 per cent. salt 
solution, fibrillated for twenty minutes, and then pulsated for seven to forty minutes, 
at first irregularly, then regularly, then at long intervals, and finally only upon 
stimulation. If, however, the ventricle was fed through a coronary artery in a 
normal manner with normal dog’s blood, by means of uniting the coronary directly 
with the femoral or carotid of another dog, the pulsations continued only so long 
as the coordination apparatus was not disturbed. 
As soon as the vasomotor centre in the septum ventriculorum was stimulated 
either through a stab or through electrical excitation, the ventricle began to 
fibrillate and continued without recovery. 
If, after the circulation of normal blood, various abnormal mixtures were used, 
the same heart began, in most cases, to pulsate, more or less regularly. 
In one instance we saw the dog's heart which was being perfused with normal 
blood, fibrillate for twenty-three minutes, and then, upon perfusing with equal parts 
of warmed defibrinated blood from the same dog and 0°6 per cent. salt solution, to 
continue fibrillation for fifty-eight minutes more. 
Perfusion with simple normal salt solution failed to preserve either fibrillation 
or pulsation. The parts perfused became cedematous, and failed to beat, while 
neighbouring parts, not supplied with salt solution, continued to contract. 
A flap of the left ventricle which had been dissected away from the rest of the 
wall so as to remain connected only by muscle at its base, and by its artery and 
veins, pulsated with a slower rhythm than the rest of the heart. 
After the vessels supplying this flap had been tied, the ventricle was caused 
caused to fibrillate ; the flap continued to pulsate as before. 
In another case the flap fibrillated with the ventricle, but resumed pulsations 
after the ligature of its vessels. 
In the third similar experiment, the flap continued to fibrillate after the ligature 
of its vessels. 
