At the present time it is well known that the development of Ascaris lumbricoides does not occur directly after the embryonate forms are ingested. After the eggs are swallowed, the larvae escape and penetrate the intestinal mucosa, gain access to the blood stream and are carried through the liver and heart into the lungs, where they act as emboli in the capillaries and whence they escape into the alveoli. From the alveoli they migrate into the bronchi, trachea, larynx and esophagus. They pass through the stomach into the small intestine, where they develop into adult worms. Stewart1first demonstrated the presence of larvae of Ascaris suis in the liver and lungs of rats and mice following the feeding of these experimental animals with ripe eggs. Ransom and Foster2confirmed Stewart's observations and extended their experiments until they were able to show that, following the ingestion of ripe eggs