use some vitalizing
element has been added or subtracted.

This vitalizing element, though analogous to electricity, is not
identical with it. We find it absent in a room that has been recently
plastered, and is not quite dry. Sleeping in such a room is positively
dangerous. We find the same negative depressing condition wherever
evaporation has been going on in the absence of sunlight, which
appears to supply the needful element.

As evaporation carries off this vitalizing element, precipitation or
condensation seems to supply it, especially precipitation from the
upper regions of the atmosphere to which it is carried by evaporation,
and to which it is supplied by sunshine. Hence we experience a
delightful freshness of the atmosphere after a summer shower, or on a
frosty morning, when the moisture is not only precipitated, but
condensed into frost. Frost gives off more of the exhilarating element
of watery vapor than dew, because it is a step farther in
condensation. Hence there is a healthful, bracing influence in cold
climates, where all the moisture is firmly frozen, and a very
unpleasant, depressing influence when a thaw begins. The vicinity of
melting snow, or a melting iceberg, is unpleasant and promotive of
catarrh and pulmonary diseases.

The pleasant influence of the fresh shower ceases when the fallen
moisture begins to evaporate, and the dewy freshness of the early morn
before sunrise ceases as the dew evaporates. The most painfully
depressing atmosphere is that which sometimes comes in cold weather
from Northern regions which have long been deprived of sunshine.

This element of health, which physiologists have neglected to
investigate, has recently been sought by Dr. B. W. Richardson of
England. The Popular Science News (of Boston) says:--

"Dr. B. W. Richardson of England, in making some investigations
upon the physiological effects of breathing pure oxygen by
various animals, has discovered, that, by simply passing the gas
a few times through the lungs, it becomes "devitalized," or
incapable of supporting life, although its chemical composition
remains the same, and all carbonic dioxide and other impurities
are removed. He also found, that, by passing electric sparks
through the gas, it became "revitalized," and regained its usual
stimulating effect upon the animal economy. The devitalized
oxygen would still support life in cold-blooded animals, and
comb