1.8 
DR. W. MARCET OX A CHExMICAL IXQUIRY INTO 
The first series of experiments refers to William Alderwood, aged 23, a strong 
man in excellent health, with a well developed chest measuring 83 centims. in 
circumference at nipples ; he weighs 8 st. lib. without clothes. Seventy-four com¬ 
plete experiments were made in his case, but as they extended from the winter 
into the spring, the temperature of the la-boratory (heated by hot water pipes) under¬ 
went rather great changes during that period; this circumstance was found to exert 
a decided influence on his respiration, the cold reducing the volumes of air breathed 
for 1 grm. COo expired; hence it became necessary to divide the 74 experiments 
into two groups, one group including those made at a laboratory temperature varying 
from 14° to 17°‘3 C., and the other group including those made at a temperature 
varying from 17°‘3 to 21°‘7 C. 
The first group numbered 25 experiments, and the second 49 experiments. The 
results are given in the form of tables, the means of which have been made into two 
charts or series of curves (see Plate 1 ). Each chart shows three curves, one for the 
carbonic acid, one for the volumes of air expired, and one for the relation between the 
volumes and the corresponding weights of carbonic acid. 
[In relatively cold weather (14° to 17°’3, see table, p. 19) it is difficult to define the 
precise hour during which the maximum carbonic acid is expired, as the proportion 
exhaled is relatively high from 0 to 1 hour, 1 to 2 hours, and 2 to 3 hours after food; 
the actual maximum is from 2 to 3 hours after food, after which time the fall is 
marked and continued. In relatively warm weather (17° to 21°‘7, see table, p. 21 ) it 
is also difficult to assign the period for the maximum expiration of carbonic acid, the 
highest figure is between 1 and 2 hours after a meal, but the fall does not begin till 
the fourth hour. It may be said that with this person under experiment, the expira¬ 
tion of carbonic acid begins to lessen somewhat earlier after food in cold weather than 
in warmer weather; but it would be premature to apply this result in a general way. 
The chart for the comparatively cold u'cather (William Aldeewood under experi¬ 
ment) shows distinctly, from an inspection of the curved line marked CO.3, that the 
carbonic acid expired is high (with a slight fall from 1 to 2 hours after food) till from 
2 to 3 hours after food, after which time the fall is rapid and regular till from 5 to 6 
hours after food, when the experiments come to an end. In this same chart the curve 
for the volumes of air expired in comparatively cold weather (see the dotted line) 
coincides very closely with the curve for COo, from 2 to 3 hours till from 3 to 4 
hours, and from 4 to 5 hours till from 5 to 6 hours, after food ; then, while the line for 
CO.3 falls fast and regularly, that for volumes of air expired remains nearly hori¬ 
zontal for an hour (from 3 to 4 hours till from 4 to 5 hours after food) ; this means that 
the volumes of air are increasing in proportion to the weight of COo they contain, 
hence the curve for relations shoots up rapidly ; but in the following hour (from 4 
to 5 till from 5 to 6 ) the curves for volume and CO 3 show again a marked tendency 
to coincide. 
In the chart for the rclailrchj u'ann ivealhcr (William Aldepavood under experi- 
