rasite
has unquestionably existed over the area just named since the advent of
the Negro--recent investigations having shown that the worm is in all
probability of African origin. This hook-worm disease is probably the
most common of all the serious diseases prevalent in the South, and as it
is easily curable, and can be readily prevented, there is no matter which
should be of greater interest to the people in the infected regions,
especially those who live in villages or on farms.

_Character of the Disease._--The animal parasite called hook-worm closely
resembles, externally, the pin-worm which so often occurs in children.
The female, which is larger than the male, measures somewhat more than
half an inch in length, and has the thickness of a knitting-needle; the
male is between a quarter and three-eighths of an inch in length as a
rule. The parasite possesses around its mouth a row of minute plates
somewhat resembling hooklets, by means of which it grasps hold of the
mucous membrane of the intestine and bruises it sufficiently to cause the
blood to flow; with this blood the parasite nourishes itself. At the same
time the worm injects into the tissues a poison which has much to do with
the symptoms that occur in the disease that it produces.

These worms are usually present in great numbers, there being as a rule
from 500 to 2,000 of them, and as they unquestionably live at least eight
or ten years, the unfortunate victim suffers for a long period of time as
a result of their presence. While living in the intestines the females
lay enormous numbers of eggs which pass out with the feces, and under
suitable conditions of temperature and moisture there develops within
each of them, within from two to three days, a minute snake-like embryo
which bursts through the shell of the egg and passes into the neighboring
earth. Here the embryos live for considerable periods of time, and,
ultimately, may infect other individuals, or those from whom the eggs
were passed. There are at least two ways by which these embryos gain
entrance into the human body. Some do so by getting into drinking-water
and being swallowed; but, extraordinarily, they most frequently penetrate
through the skin. When this happens the parasite, in passing through the
skin, produces the disease known as "ground-itch." The vast majority of
the victims of this affection are children with whose skin the embryo
comes in contact while they go barefooted during the