PHYSIOLOGIOAL EFrFects oF Lack or Oxyaen 411 
Ihave repeated this experiment eight times, always with 
It was of importance now to determine 
whether the number of heart-beats increases, and how much 
it increases, when a heart which has attained its minimum 
rate in hydrogen is again exposed to the oxygen of the air. 
the same result. 
100 = 
— SJeIg7 74% HY 
3 
L 
In one such experiment the current of 
hydrogen was turned on at 9:10 a. Mm. 
The number of heart-beats was 120 per 
minute. At 11 the number of heart-beats 
had fallen to 42, and soon thereafter the 
minimum of 24 heart-beats was reached. 
At 2:40 the number of heart-beats was 
still 24. At 2:44 the embryo was taken 
out of the gas-chamber and brought 
into fresh water, and at 2:48 the num- 
ber of heart-beats was counted; it was 
then 30. The further 
course of the experi- 
ment is shown in the 
following table: 
4o Ry’) bo qo 80 70 joo 0 
POinu bes 
FIG. 125 
40 beats per minute 
51 “co ce “6 
60 “a ae “ce 
66 ae 66 a“ 
fe 66 be be “ 
69 (79 ae “c 
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