mmunity. They are the screening of patients to prevent spreading
the disease; screening all houses closely and keeping close watch for
mosquitoes in the house, and covering all ponds in the neighborhood with
oil. New Jersey mosquitoes were formerly known far and wide, but such an
active campaign has been waged against them, that they have been almost
completely driven from the state.

The ordinary mosquito has never been found to do any harm beyond the
discomfort of its bite.

Of other diseases caused by insects, an affection of the eyes called
pink-eye is carried by very tiny flies, and the dreaded bubonic plague
is supposed to be transferred from sick people to well ones by the bites
of fleas, which in turn are brought to this country by rats.

The hook-worm which affects so many persons in the South is often called
"the lazy disease" since the persons afflicted with it are not totally
disabled, but are lacking in energy and vigor because the small insects
take from the blood the red corpuscles which should carry the digested
food all over the body. These insects can be destroyed by medicine, of
which only a few cents worth is required to cure a case and make the
patient fit for work and enjoyment. In Porto Rico almost 300,000 cases
have been treated by the United States government in the last six years.

Another matter which should receive careful consideration is the large
number of preventable accidents. Mining accidents come in a few cases
from failure to provide the best appliances in the mines, but in many
cases are due to carelessness or ignorance of the operators themselves.
There still remain a large number of accidents which occur in the best
regulated mines, and when no instance of special carelessness can be
traced. For years these disasters have puzzled mining engineers, but
within the last few months it has been discovered that the minute
particles of coal dust in a dry mine completely fill the air, so that
the air itself is ready to burn.

When a light is taken into this coal-filled atmosphere, it bursts into
flame, causing a violent explosion. Sprinkling the mines, forcing a fine
spray of water through the air of every part of the mines, it is
thought, will prevent this class of accidents, which have furnished long
lists of killed and injured each year.

Reports show that one miner is killed and several injured for every one
hundred thousand tons of coal mined. The mining accidents of one year
to