XXTI1.—Isrivence or Some OrGanic anp INoRGANIC SuB- 
sTANCES ON Gas Merasonism. By R. H. CutrrenpEN AND 
G. W. Cummins, Pu.B. 
Wuite much time has been spent during the past few years in 
studying the influence of various substances on proteid metabolism, 
far less attention has been paid to the effects of these substances on 
the consumption of oxygen and the elimination of carbonie acid. 
Naturally in studying the influence of any substance on the nutrition. 
of the body, we need to know not only its action on the excretion of 
nitrogen but also its influence on the production of carbonic acid. In 
this way only can we arrive at a true understanding of the influence 
of the substance on total metabolism, and obtain the necessary data 
from which to draw conclusions as to its influence on the consump- 
tion of either nitrogenous or non-nitrogenous matter. The difficulties, 
however, in the way of carrying on consecutive determinations of the 
relative amount of carbonic acid eliminated by the lungs are consid- 
erable, and in the absence of the necessary respiration apparatus, the 
difficulties are greatly increased. We have, however, endeavored to 
carry on some experiments in this direction, and although lacking 
the ordinary apparatus we have still been able with the means at our 
disposal to obtain some interesting results, a portion of which are 
simply confirmatory of previous work, while others are wholly new. 
The apparatus employed in measuring the amount of carbonic acid 
eliminated is shown in the accompanying illustration (see Plate). The 
chamber in which the animal was placed during the experiment, was a 
bell jar of 32 litres capacity, with ground edge fitting closely upon a 
smooth glass plate. This when coated with grease made a perfectly 
tight joint, but in order to avoid any possibility of error, the jar and 
plate were placed in a shallow pan of galv anized iron, and water poured 
in to the depth of 2-8 inches, thus insuring a perfectly air-tight joint. 
In the top of the bell jar was an opening, closed with a doubly perfor- 
ated rubber stopper, through which passed two tubes; one bringing 
air into the chamber, the other carrying it to the absorption apparatus. 
The inlet tube (to the left of the figure) was prolonged so as to admit 
the air nearly at the bottom of the jar, while the outlet tube came 
just through the stopper, thus insuring a perfect circulation of air, 
Air was drawn through the chamber by means of three aspirators, 
