The author studied statistically 160 cases of hookworm infection who had been admitted to Misasa Branch of Okayama University Hospital, Misasa Hot Springs in Tottori prefecture, during 1946~1949 and 162 cases of out-patients with anchylostomiasis in Yakage Hospital, Okayama Prefecture, during 1949～1950. The clinical findings were as follows: (1). Females showed a higher incidence than males and the incidence ratio of infected persons to total out-patients increased with age up to the 50~69 years group. (2). The most patients consulted our hospital for the first time in April～May and in August, and 62 per cent of cases came within 3 months scince they had noticed disorders in some way, but 22% remained at home without medical cure more than
a year. (3). Chief subjective complaints were palpitation of heart (35.3%), lassitude of legs (31.2%), pains in the abdomen (22.9%), feeling of dizziness (21.6%) and so on. (4). Laboratory findings: The total number of erythrocytes was between 1.23 and 5.54 millions per cubic millimeter and a moderate anemia almost always developed in the hookworm disease (77.9% of all cases). The number of white cells was normal or slightly increased. Relative or absolute eosinophilia was recognized in 83.5% of all patients. Wassermann's test was positive in 20%, and Takata's reaction positive in 53% of the cases. The acidity of the gastric juice was lower than normal. Hypo- and anacidity were verified in 58%. Both albumen and urobilinogen test in urine were positive in 5.4% of 61 cases. Sugar in none. (5). Treatment: Thymol, tetrachlorethylene and oil of chenopodium were used alternately to remove the worms. The eggs in stool became negative after 3-4 times of the administration of anthelmintics in 76 per cent of 151 cases. As mentioned above, the patients infected with hookworm had various functional disorders of bodies, but they consulted the hospital only when the farmer's busy season began and their trouble became unbearable. And then the recovery of anemia took a month or two. Prof. Kitayama reported that the cold environment under 9°C. in the winter had perished the larva of hookworm in the soil. From these viewpoints, the author proposed that examination and cure of hookworms should be carried out in the winter, the slack season for farming, to prevent the fall of working ability due to anchylostomiasis during the busy farming seasons.