342 CO, Capacity of Blood. I 
In Experiment 7 morphine was administered and the animal 
was then made to rebreathe (by means of a mask and Douglas 
bag) air of a CO, content at first practically the same as the 
~normal alveolar air and rising gradually to 8.2 per cent. The 
CO, content of the blood rose in 1 hour and 10 minutes to 76 
and the CO, capacity to 67. 
Experiment ?.—Dog, male, 8 kilos. Morphine and CO, administration. 
Procedure same as Experiments 3 to 6 except that dog rebreathed into a 
large bag, which in the beginning contained 5 per cent CO,. Equilibrating 
air 5.5 per cent CO. 
Blood COs. 
Time. Condition. ot oe Bed 
: Content. | Capacity. ture. 
p.m. per cent |vol. per cent|vol. per cent eCt 
3.35 Normal. 48 50 39.9 
4.00 Morphine, 0.12 gm. 
4.20 Breathing COs. 5.1 
4.40 % “ 70 06 
5.10 3. re 69 64 40.0 
5.15 4 a 8.2 
5.30 if t 76 67 
6.00 ie “ 74 66 
Finally three experiments were performed in which no morphine 
was administered, but the rebreathing from the bag was begun 
with about 6 per cent of CO, and continued until the CO, had - 
accumulated up to 10, 11, and 20 per cent respectively. (Ample. 
oxygen was supplied.) Of course the breathing was stimulated 
to violent activity at percentages between 6 and 10, but much 
less above 10 per cent. ‘The effects on the blood were of exactly 
the same character as in the experiments in which respiration 
was depressed and the alveolar CO, raised by means of morphine. 
The CQ: content was forced up (to 74, 73, and 87) and the CO; 
capacity followed it upward (to 64, 59, and 74). When the re- 
breathing was stopped and the animal again allowed to breathe 
normal air, the CO, content led the CO, capacity downward 
toward normal values again, but the descent was slow and gradual. 
