Developmental Studies Concerning the Eggs of Ascaris lumbricoides var. suum

The literature reveals that velocity curves for developmental stages of parasitic worms have not been reported. Many authors have studied the development of parasite ova and larvae but in each case they failed to present comprehen-sive information regarding and humidity effects. The majority of such reports merely give the period required for development to a given stage under natural or at a particular or at the minimum, maximum, or optimum temperature. For instance, Leuckart (1876) observed complete embryonation of the ova of Ascaris lumbricoides (human) in forty days at mid-summer temperatures; Raillet (1893) reported that at a favorable temperature Ascaris lumbricoides var. suumn ova contained motile embryos in thirty to forty days; and Wharton (1915) observed embryonation of Ascaris lumbricoides (human) ova in fifteen days at summer temperatures in the Philippine Islands. Similarly, Brown (192-7a) reported embryonation of Trichuris trichiura ova in twenty-one days and of A. lumbricoides (human) ova in fifteen days under field conditions in Panama.