the
Charles River, in the country near Boston. It is common in the
vicinity of the cities of Philadelphia, New York, and Baltimore, but
here is less frequent than formerly, and is of a comparatively mild
type. More severe forms prevail along the Gulf of Mexico and the
shores of the Mississippi and its branches, especially in Mississippi,
Texas, Louisiana, and Arkansas, but even here it is less fatal and
widespread than formerly. In Alaska, the Northwest, and on the Pacific
Coast of the United States malaria is almost unknown, while it is but
slightly prevalent in the region of the Great Lakes, as about Lakes
Erie and St. Clair.

=Development.=--Usually a week or two elapses after the entrance of
the malarial parasite into the blood before symptoms occur; rarely
this period is as short as twenty-four hours, and occasionally may
extend to several months. It often happens that the parasite remains
quiescent in the system without being completely exterminated after
recovery from an attack, only to grow and occasion a fresh attack, a
month or two after the first, unless treatment has been thoroughly
prosecuted for a sufficient time.

=Symptoms.=--Certain symptoms give warning of an attack, as headache,
lassitude, yawning, restlessness, discomfort in the region of the
stomach, and nausea or vomiting. The attack begins with a chilliness
or creeping feeling, and there may be so severe a chill that the
patient is violently shaken from head to foot and the teeth chatter.
Chills are not generally seen in children under six, but an attack
begins with uneasiness, the face is pinched, the eyes sunken, the lips
and tips of the fingers and toes are blue, and there is dullness and
often nausea and vomiting. Then, instead of a chill, the eyelids and
limbs begin to twitch, and the child goes into a convulsion. While the
surface of the skin is cold and blue during a chill, yet the
temperature, taken with the thermometer in the mouth or bowel, reaches
102 deg., 105 deg., or 106 deg. F., often. The chill lasts from a few minutes to
an hour, and as it passes away the face becomes flushed and the skin
hot. There is often a throbbing headache, thirst, and sometimes mild
delirium. The temperature at this time, when the patient feels
intensely feverish, is very little higher than during the chill. The
fever lasts during three or four hours, in most cases, and gradually
declines, as well as the headache and general distressing symptoms
with the