22 
DR. W. MARCET ON A CHEMICAL INQUIRY INTO 
Relation between Volume of Air expired [reduced) and Weight of Carbonic 
Acid; i.e., Volume of Air expired for 1 grm. CO^. 
Hours after a meal. 
0 to 1. 
1 to -2. 
2 to 3. 
3 to 4. 
4 to 5. 
5 to 6. 
9-34 
8-78 
8-93 
8-94 
9-58 
9-73 
9T2 
9-25 
9-45 
9-16 
9-54 
9-87 
9-29 
9'5.5 
9-45 
9-23 
9-62 
10-39 
9-45 
9-52 
9T3 
9-25 
9.80 
10-03 
9-51 
9-52 
9-.35 
lO-OI 
9-69 
9-35 
9-27 
9-77 
9-60 
9-69 
9-05 
9-55 
9-66 
9-95 
9-47 
10-23 
9-78 
10-41 
9-66 
9-54 
10-07 
9-69 
9-44 
9-79 
9-60 
Mean.s 9'34 
9-33 
9-24 
9'27 
9-72 
9-83 
Infuence of Abnospheric Pressure on Respiration, 
[Ill order to make the influence of atmospheric pressure on respiration perfectly 
clear to the reader, the experiments have been disjiosed in the form of two tables. 
In the first table they are divided into two groups (under the form of means) of an 
equal number, the first group including the experiments attended with the highest 
barometer readings, the second including those attended with the lowest readings. In 
the second table (pp. 23 and 24) each of the groups of experiments considered (under 
the form of means) in the preceding table, has been divided into two sub-groups 
of an equal number of experiments, each of the sub-groups for the extreme highest 
and extreme lowest pressures only being entered (under the form of means).— 
October 23, 1889.] 
It is certainly unexpected to find that local changes of atmospheric pressure have 
a most positive and marked influence on respiration, the effect being of the same kind 
as that I had observed previously in my experiments at increasing altitudes. In order 
to show the action of the variations of local pressures on respiration it was necessary 
to eliminate as much as possible the influence of food, and with this object in view 
the experiments made every two hours after a meal were grouped together, and the 
]jressures and corresponding relations for each group placed in a tabular form. 
