The third parasitical disease common in some parts of the United States has received much attention during this last year and is known as the hookworm disease. It is a new discovery in medical science, and whereas the physical condition of the victim is usually a clear indication of the disease, a positive diagnosis is always obtained by the use of the microscope. Several years ago it was announced in the United States that the laziness and shiftlessness of the poor whites living in the sand lands and pine barrens of the South was due, not to any inherent cussedness but to the presence of a parasite in the intestine, known in Italy and Germany as the hookworm, the disease being called Uncinariasis. The development of the disease is interesting. The worm, which is about an inch long and looks not unlike a bit of thread, lays eggs by the thousand in the intestinal tract of a human victim. Afterwards they pass out in the excreta and, favored by heat and moisture, develop in the soil in about three days into minute larvae. These larvae have a most extraordinary power of attaching themselves to and penetrating into the human skin and body. They may also enter the human body in a drink of water or on unwashed vegetables. In infected regions the soil becomes fairly alive with these larvae, and it is hardly possible for a child to walk barefoot outdoors without becoming infected. When the larvae have penetrated the hand or foot, they begin a long and circuitous journey through the body, moving from the extremities through the veins to the heart and thence to the lungs. From here they are carried through air cells into the bronchial tubes, thence along the mucous membrane up the windpipe and down into the stomach and finally, from the stomach, they pass out into the intestines, the goal of their long journey. This all takes time, and probably from the time they enter the skin to the time they begin their murderous work on the lining of the intestines requires about two months. In the intestine the larvae develop into adults; but before this final stage an intermediate existence is reached, at which time they attach themselves to the mucous lining and bore into it, presumably for the purpose of making a nest in which later to lay their eggs. The burrowing parasite causes a great loss of blood, and it is on account of the resulting anaemia that the poor whites show always such incapacity, indifference, and apparent laziness. That this disease is of importance in considering the hygienic condition of the country is apparent when it is pointed out that in the southern part of the United States, chiefly in the rural districts, there are at least two million persons at present infected with the disease, and that should these hookworms be blotted out of existence, two million incapables would be changed into two million active Americans, ready to raise the southern districts to a commercial elevation which their natural resources seem to justify.