r form.

=Black Water Fever.=--Rarely in temperate climates, but frequently in
the Southern United States and in the tropics, especially Africa;
after a few days of fever, or after chilliness and slight fever, the
urine becomes very dark, owing to blood escaping in it. This sometimes
appears only periodically, and is often relieved by quinine. It is
apparently a malarial fever with an added infection from another
cause.

=Chagres Fever.=--A severe form of malarial fever acquired on the
Isthmus of Panama, apparently a hemorrhagic form of the pernicious
variety, and so treated.

=Detection.=--To the well-educated physician is now open an exact
method of determining the existence of malaria, and of distinguishing
it from all similar diseases, by the examination of the patient's
blood for the malarial parasite--its presence or absence deciding the
presence or absence of the disease. For the layman the following
points are offered: intermittency of chills and fever, or of fever
alone, should suggest malaria, particularly in a patient living in or
coming from a malarial region, or in a previous sufferer from the
disease. In such a case treatment with quinine will solve the doubt in
most cases, and will do no harm even if the disease be not malaria.
Malaria is one of the few diseases which can be cured with certainty
by a drug; failure to stop the symptoms by proper amounts of quinine
means, in the vast majority of cases, that they are not due to
malaria. There are many other diseases in which chills, fever, and
sweating occur at intervals, as in poisoning from the presence of
suppuration or formation of pus anywhere in the body, but the layman's
ignorance will not permit him to recognize these in many instances.
The quinine test is the best for him.

=Prevention.=--Since the French surgeon, Laveran, discovered the
parasite of malaria in 1880, and Manson, in 1896, emphasized the fact
that the mosquito is the medium of its communication to man, the way
for the extermination of the disease has been plain. "Mosquito
engineering" has attained a recognized place. This consists in
destroying the abodes of mosquitoes (marshes, ponds, and pools) by
drainage and filling, also in the application of petroleum on their
surface to destroy the immature mosquitoes. Such work has already led
to wonderful results.[11] Open water barrels and water tanks prove a
fruitful breeding place for these insects, and should be abolished.
The protec