BLOOD SUCKING ACTIVITIES OF HOOKWORMS ROUTES AND QUANTITIES OF BLOOD LOSS IN ANCYLOSTOMA CANINUM, A DUODENALE AND A CEYLANICUM INFECTIONS*

In vivo continuous observations made se- parately on 41 female and 19 male worms of Ancylostoma caninum reveal that the average volume of blood sucked by each female or male worm from infected dogs was 43.1 (+39.6) and 12.9 yi/24 hr. There was always further bleed- ing from the mucosal la.ceration at the site of attachment while the worm was sucking ac- tively. Separate observations made on 35 lacera- tions induced by female and 14 by male worms of A caninum reveal that the blood Jost averages 46.1 (+39.1) and 15.8 ul/24 hr/laceration for fe- male and male worms. The volume of blood loss through two routes correlates closely, the coefficient being 0.618. As only about 42'70 0f the worm population actively suck at a given time, it seems logical to adjust these Z sets of figures with a coefficient 4270. Observations are made on 37 female and 13 male worms of A caninum to ascertain the quantity of blood lost from the wound when the worm moves on to a new site, the values obtained are l.5 and 0.3 L1l/24 hr/worm for female and male worms. A considerable amount of blood is also lost through "extensive intestinal hemorrhage" which occurs occasionally. In generaj, the amount of blood lost through bleeding external to the worm is greater than that lost through the hookworm. Preliminary studies on A duodenale a.nd A cey- lanicum supplement the impressions gained on A caninum.