400 SLR THOMAS B. FRASEK AND MR AL1STER T. MACKENZIE ON 



At 3.23.40 the blood-pressure rose from 14 mm. to 42 mm. It then fell rapidly 

 to zero and did not rise again, though respiratory convulsions occurred at 3.26 and 

 afterwards. 



At 3.35, the heart was exposed ; it was motionless and did not respond to mechanical 

 stimulation. The right auricle was large and dark blue in colour ; and the left auricle 

 was moderately large and mottled dark blue and bright red. The right ventricle was 

 small and contained dark venous blood, and on section it was found not to be tightly 

 contracted. The left ventricle was small, and on section a small quantity of bright red 

 blood was found in it ; its cavity was not obliterated, and its muscle was faintly acid in 

 reaction to litmus paper. 



In this experiment, the blood-pressure rose immediately after injection, and for 

 about 5 minutes (until 12.23.50) (fig. 5) the average pressure was greater than before 

 injection ; thereafter the pressure fell gradually, except for some periods of spasmodic 

 increase, as at 12.28.40 (fig. 7). The lowest average pressure occurred at 1.55.10. 

 Thereafter the blood-pressure gradually rose, but did not attain the height at which it 

 had been before the injection. After the second injection at 3.18.50, the blood-pressure 

 rose for a brief period, but its height oscillated rapidly and within four minutes it had 

 fallen to zero. 



The pulse movements became distinctly increased during the initial rise of blood- 

 pressure and showed an irregularity occurring at every second movement ; the rate of 

 the pulse was also increased during this period. As the blood-pressure fell, the pulse 

 movements became more feeble (fig. 5), and when the most rapid variations in blood- 

 pressure were occurring (fig. 6) these movements were very indistinct. When the 

 average blood-pressure was lowest (1.55.10), the pulse-rate had returned to the normal, 

 but the pulse movements were still very feeble. The secondary gradual rise in the 

 blood-pressure was accompanied by an improvement in the pulse movements (fig. 10). 

 The pulse movements showed no improvement after the second injection, and they 

 rapidly became extremely feeble, 



An increase in the rate and in the size of the respiratory movements accompanied 

 the initial rise of blood-pressure. The greatest increase in the respiration rate and 

 movements coincided with the greatest oscillations in blood-pressure, and with the 

 greatest rapidity of the pulse (12.28.40) (fig. 7). Thereafter the respirations became 

 slowed, but their movements continued to be larger than before injection. They 

 remained regular in time and of large size after the second injection, until the blood- 

 pressure fell to zero. This fall in blood -pressure was followed by respiratory 

 convulsions. 



[Experiment LXX. 



