ON THE HEART OF THE DOG. 
149 
May 2, 1882.—Weight of Dog, 8610 grms. Weight of heart, 76 grms. 
Observations. 
Time, p m. 
Temp. C. 
in superior 
cava. 
Beats in 
30 seconds. 
Arterial 
pressure in 
carotid. 
Millims. of 
mercury. 
Venous 
pressure in 
superior cava. 
Centims. of 
blood. 
Outflow in 
30 seconds. 
Cub. centims. 
Outflow in 
1 beat. 
Cub. centims. 
Work done 
at each 
systole of 
the left 
ventricle 
in gramme- 
metres. 
1 
h. 
3 
m. 
46 
34° 5 
82 
120 
20 
385 
4-69 
7'59 
2 
3 
48 
3525 
83 
84 
20 
375 
4-52 
5-13 
3 
3 
49 
35 + 
83-5 
58 
20 
360 
431 
3-40 
4 
3 
51 
34-5 
82 
107 
20 
372 
4‘54 
6 - 56 
5 
3 
53 
35 
79-5 
138 
20 
345 
4-34 
8-09 
6 
3 
55 
35 
82 
147 
20 
365 
4 - 45 
8-82 
7 
3 
56 
35- 
81-5 
136 
20 
361 
4-43 
8-13 
8 
3 
57 
3475 
8T5 
62 
20 
350 
4-29 
3-59 
It is seen from the tables that variations of arterial pressure from 58 to 147 millims. 
of mercury have practically no effect •whatever on the quantity of blood sent out from the 
ventricle at each systole. The small differences that appear easily come within the 
limits of error. The methods of catching the blood is one that will unavoidably 
introduce small errors. Another source of error is connected apparently with the use 
of Calf’s blood. After the heart had been working in the case for some time, it was 
almost always found that the pericardium was tightly filled with exuded serum, 
preventing complete distension of the ventricle during diastole, and consequently 
diminishing the outflow—in such cases by cutting a slit in the pericardium the out¬ 
flow would immediately increase. 
The observations given in the table were all taken before this filling of the 
pericardium had become sufficiently advanced to cause any important error ; in later 
observations in the course of the same experiments its influence was very marked. 
The figures as they stand, however, show clearly, as we have said, that, within the 
limits given, variations of arterial pressure have no direct effect on the amount of 
blood thrown out from the left ventricle. For how much wider limits than those 
indicated this statement may be true, we cannot yet say. It is also clear that, as 
Professor Martin had already proved (10), the pulse-rate remains unchanged. Since 
now the work done by the contraction of the ventricle depends on two factors, viz., 
the amount pumped out at each systole, and the height to which this amount is 
raised, and one of these factors remains practically constant, it follows that the 
work done by the left ventricle of the Dogs heart varies directly as the arterial 
pressure against which it works within the limits named above. 
Blasius (6), in his experiments on the isolated Frog’s heart, found that the work 
of each single beat increased for a time with increase in arterial pressure, but that, 
nevertheless, “ die Intensitat des Wachsthums mit nur wenigen Ausnahmen allmahlich 
abnimmt. ” 
