340 CO, Capacity of Blood. I 
In the next four experiments, after a preliminary normal 
period in each case, morphine was administered subcutaneously. 
The extent of the depression of respiration may be judged by the 
rise in the alveolar CO, from the normal of about 5.3 up to 
amounts ranging from 6.1 to 6.9. In one case (Experiment 6) 
this rise was comparatively slight at first (owing to the animal 
being of an excitable character and breathing correspondingly) 
and in the columns showing the CO, content and CO, capacity 
the effects are correspondingly slight. Later in this experiment 
and in all of the experiments in which the alveolar CO: attained a 
high level, the CO, content of the blood invariably followed it, 
and the CO, capacity followed the CO, content with a lag of 20 
to 30 minutes. Thus the CO, content rose from about 50 up to 
values ranging from 68 to 67, and the CO, capacity from about 
50 up to values of 59 to 64. 
Experiment 3.—Dog, male, 14 kilos. Morphine administration, de- 
pressed respiration, followed by rise of CO, content and CO: capacity. 
Equilibrating air 5.7 per cent CO. 
Blood COz. wes 
Time. Condition. Alveolar | 2 ae tempera- 
3 . ture. 
Content. | Capacity. 
per cent |vol. per cent|vol. per cent 3 6s 
9.30 a.m. | Normal. One 52 52 - 39.9 
10.00 “ pat 52 53 
10:0by Morphine, 0.14 gm. 
1OsMOg Vomiting and panting. 
10.40 <“‘ Quiet. 6.6 57 48 
i200 ae 60 53 37.8 
12:00 oy Quiet. 6.6 | 62 54 
12.30 .* a 62 56 
1.30 p.m. a 6.9 67 59 
210a x 63 60 36.6 
2.40 “‘ ae 58 59 
3.30 “ 6.8 64 62 
6.00 “ Struggling. 4.8 49 56 37.0 
