tarch. Or bibulous paper can be
dipped in the starch, dried and cut into slips, and these slips being
placed in the air will indicate when ozone is present. In disinfecting
or purifying the air of a room with ozone, there is no occasion to
stop until the test paper, by change of color, shows that the ozone
has done its work of destroying the organic matter which is the cause
of impurity or danger. For my own part, I have never seen the
slightest risk from the use of ozone in an impure air. The difficulty
has always been to obtain sufficient ozone to remove the impurity, and
it is this difficulty which I hope now to have conquered.--_The
Asclepiad._

* * * * *

HEAT IN MAN.

At a recent meeting of the Physiological Society of Berlin, Prof.
Zuntz spoke on heat regulation in man, basing his remarks on
experiments made by Dr. Loewy. The store of heat in the human body at
any one time is very large, equal, in fact, to nearly all the heat
produced by the body during twenty hours, hence the heat given off to
a calorimeter during a given period cannot be taken as a measure of
the heat production. This determination must be based rather upon the
amount of oxygen consumed and of carbonic acid gas given off. The
purpose of the experiments was to ascertain what alteration the
gaseous interchange of the body undergoes by the application of cold,
inasmuch as existing data on this point are largely contradictory.

The observations were made on a number of men whose respiratory gases
were compared, during complete rest, when they were at one time
clothed, at another time naked, at temperatures from 12 deg. to 15 deg. C.,
and in warm and cold baths. Each experiment lasted from half an hour
to an hour, during which period the gases were repeatedly analyzed. As
a result of fifty-five experiments, twenty showed no alteration of
oxygen consumption as the result of cooling, nine gave a lessened
consumption, while the remaining twenty-six showed an increased using
up of oxygen. This diversity of result is explicable on the basis of
observations made by Prof. Zuntz, who was himself experimented upon,
as to his subjective heat sensations during the experiments. He found
that after the first impression due to the application of cold is
overcome, it was quite easy to maintain himself in a perfectly passive
condition; subsequently it required a distinct effort of the will to
refrain from shivering and th