380 
POPULAR SCIENCE REVIEW. 
In this instance the temperature while nude had remained 
some time at 99°*85, when immersing the feet, at 11.40, in water 
at 112°, caused the prompt fall which is here recorded. 
On a cold day anyone sitting in a large room with one side 
or the back to a warm fire for some time is fairly certain to 
feel the cold to a more than ordinary extent in the distant arm, 
or in the hands, and this is because the fire heating the parts 
exposed to its influence increases the circulation through the 
skin of both sides, and therefore allows of excessive cooling 
in the unwarmed limbs. Eheumatism of the shoulder and 
knee, and tic-doloureux, are often so caused. 
It is in the Turkish- bath that, in this country at least, the 
effects of an atmosphere hotter than 70° can be best investigated. 
There is, however, a precaution with regard to the thermometer 
itself which must always be taken in employing it in an air 
exceeding 110°. This being about the highest point to which 
the clinical instrument is generally graduated, and to which 
its tube extends, any much greater heat will split it. A fair- 
sized mercury reservoir at the end of the tube will obviate 
this difficulty ; but then the thermometer cannot be a self- 
registering one, as it would be impossible to keep the small 
detached index from joining the main column at high tempera- 
tures. In the Turkish-bath it is best to employ a thermometer 
at least a foot long, not graduated near the bulb, and with a 
dilatation at its other end. This can be read off by a com- 
panion, or, better still, by the experimenter himself, with the 
assistance of a movable reflector fastened to the stem of the 
instrument two inches above it, at an angle of 45°, in such a 
manner that it can be made to slide from end to end. 
Perspiration commences very quickly when the hot room of 
the Turkish-bath is entered ; and though on going into the 
hotter chambers, one after the other, the amount of perceptible 
moisture does not appear to increase, this is because at each 
stage the evaporation becomes more rapid. This is proved by 
the excess of the cutaneous moisture, always found on first re- 
turning to the cooler rooms, when also the temperature, from 
being nearly stationary commences to rise more evidently. 
In none of my previous remarks have I included the effects 
of the water-bath, because directly the body is immersed in fluid, 
the regulating action of the skin can come but slightly into play. 
The morning tub, short in duration, and not accompanied with 
complete immersion, raises the temperature, as does exposure to 
cold air ; and a similar glow is subsequently felt. The bath has 
a very different effect if at all prolonged, even in tepid water, 
and before breakfast. Five minutes after a swim of four minutes 
duration in the sea at 74° my mouth-temperature was 96°, which 
gradually rose two degrees by the end of an hour, and another 
degree in the next hour, during which I had breakfasted. 
