e odor of ether soon becomes apparent inside of the
chamber if there is a leakage. Many leaks that could not be found by
soapsuds can be readily detected by this method.

VENTILATION OF THE CHAMBER.

The special features of the respiration chamber are the ventilating-pipe
system and openings for supplementary apparatus for absorption of water
and carbon dioxide. The air entering the chamber is absolutely dry and
is directed into the top of the chamber immediately above the head of
the subject. The moisture given off from the lungs and skin and the
expired gases all tend to mix readily with this dry air as it descends,
and the final mixture of gases is withdrawn through an opening near the
bottom of the chamber at the front. Under these conditions, therefore,
we believe we have a maximum intermingling of the gases. However, even
with this system of ventilation, we do not feel that there is
theoretically the best mixture of gases, and an electric fan is used
inside of the chamber. In experiments where there is considerable
regularity in the carbon-dioxide production and oxygen consumption, the
system very quickly attains a state of equilibrium, and while the
analysis of the outcoming air does not necessarily represent fairly the
actual composition of the air inside of the chamber, it evidently
represents to the same degree from hour to hour the state of equilibrium
that is usually maintained through the whole of a 6-hour experiment.

The interior of the chamber and all appliances are constructed of metal
except the chair in which the subject sits. This is of hard wood, well
shellacked, and consequently non-porous. With this calorimeter it is
desired to make studies regarding the moisture elimination, and
consequently it is necessary to avoid the use of all material of a
hygroscopic nature. Although the chair can be weighed from time to time
with great accuracy and its changes in weight obtained, it is obviously
impossible, in any type of experiment thus far made, to differentiate
between the water vaporized from the lungs and skin of the man and that
from his clothes. Subsequent experiments with a metal chair, with
minimum clothing, with cloth of different textures, without clothing,
with an oiled skin, and various other modifications affecting the
vaporization of water from the body of the man will doubtless throw more
definite light upon the question of the water elimination through the
skin. At present, however, we