t of heat upon the body is measured by the difference in the
actual and sensible temperatures, as recorded by the dry and wet bulb
thermometers. When both stand nearly together as they are apt to do in
a humid atmosphere, the heat becomes insufferable. In the dry climate
of Arizona such a condition cannot occur. The difference in the two
instruments is always great, often as much as forty degrees. For this
reason, a temperature of 118 degrees F. at Yuma is less oppressive than
98 degrees F. is in New York. A low relative humidity gives comfort
and freedom from sunstroke even when the thermometer registers the
shade temperature in three figures.

A dry, warm climate is a stimulant to the cutaneous function. The skin
is an important excreting organ that is furnished with a large number
of sweat glands which are for the dual purpose of furnishing moisture
for cooling the body by evaporation and the elimination of worn out and
waste material from the organism. As an organ it is not easily injured
by over work, but readily lends its function in an emergency in any
effort to relieve other tired or diseased organs of the body. By
vicarious action the skin is capable of performing much extra labor
without injury to itself and can be harnessed temporarily for the
relief of some vital part which has become crippled until its function
can be restored.

A diseased kidney depends particularly upon the skin for succor more
than any other organ. When the kidneys from any cause fail to act the
skin comes to their rescue and throws off impurities which nature
intended should go by the renal route. For this reason diabetes and
albuminuria, the most stubborn of all kidney diseases, are usually
benefited by a dry, warm climate. The benefit derived is due to an
increase of the insensible transpiration rather than to profuse
perspiration. The air of Arizona is so dry and evaporation so rapid
that an increase in perspiration is scarcely noticeable except when it
is confined by impervious clothing. The disagreeable feeling of wet
clothes which accompanies profuse perspiration in a damp climate is
changed to an agreeable sensation of coolness in a dry one.

The atmosphere of Arizona is not only dry but also very electrical, so
much so, indeed, that at times it becomes almost painful. Whenever the
experiment is tried, sparks can be produced by friction or the handling
of metal, hair or wool. It affects animals as well as man, an