154 
MESSRS. W. H. HOWELL AND F. DONALDSON 
May 2, 1882.—Weight of Dog, 8610 grins. Weight of heart, 76 grins. 
Arterial 
V enous 
pressure in 
Outflow in 
Outflow in 
Work done at each, 
systole of the left 
ventricle, in gramme- 
metres. 
Observa¬ 
tions. 
Time. 
Temp. C. 
in superior 
cava. 
Beats in 
30 seconds. 
pressure in 
carotid. 
Millims. of 
mercury. 
superior 
cava. 
Centims. of 
blood. 
30 seconds. 
Cub. 
centims. 
1 beat. 
Cub. 
centims. 
With 
arterial 
pressure 
actually 
observed. 
With 
arterial 
pressure 
= 100 
millims. 
1 
h. m. 
3 19 
37° 75 
95-5 
113 
10 
240 
2-51 
3-82 
3-39 
2 
3 21 
37 
93 
121 
20 
473 
5-08 
8-29 
6-86 
3 
3 23 
37-5 
96 
126 
30 
617 
6-42 
10-91 
8-67 
4 
3 27 
37- 
93-5 
134 
40 
780 
8-34 
15-08 
11-26 
5 
3 30 
36 + 
91'5 
135 
50 
861 
9-40 
17-12 
12-69 
6 
3 33 
35-5 
89-5 
138 
60 
982 
10-97 
20-43 
14-81 
7 
3 36 
36- 
87 
140 
65 
940 
10-80 
20-40 
14-58 
8 
3 40 
35 + 
87 
140 
70 
940 
10-80 
20-40 
14-58 
9 
3 43 
35 
84 
112 
10 
200 
2-38 
3-60 
3-21 
The great effect which increase of venous pressure and the attendant increase in the 
blood-flow have upon the total outflow from the left side of the heart, is shown in a 
striking manner by the preceding tables. From the numbers in the last column it is 
seen that the work done by the left ventricle at each systole increases ivith the venous 
pressure, but not proportionally, up to the point of maximum work. 
One must be certain in such experiments that at each venous pressure used the 
quantity of blood sent into the heart is greater than that which is pumped out; in all 
cases the possible quantity of blood which could flow into the right side of the heart 
from the flasks at the different pressures was determined beforehand, and found to 
exceed the actual quantities thrown out from the left side in any given time. 
The maximum pressure in the right auricle of the Dog during life is, according to 
Goltz and Gaule, 19'6 millims. of mercury. The pressure to which the right auricle 
was exposed in our experiments before the maximum outflow was obtained, varied 
from 27‘2 millims. to about 46 millims. of mercury. Such pressures place the right 
side of the heart under conditions different from those which exist during life. 
However the right side of the heart was affected by these high pressures, the left 
side, with which we are more immediately concerned was, as will be shown below, 
under pressures which in all probability kept within the limits of pressures to which it 
is exposed during life. 
It is certain that the most direct factor influencing the quantity of blood sent out 
from the ventricle, and hence the work done by the ventricle, is the intra-ventricular 
pressure by which the ventricle is distended during diastole. Leaving out the 
aspiratory action of the thorax, the intra-ventricular pressure during life must 
be mainly owing to the action of the auricle, since the pressure in the great veins 
