Ascariasis, or infestation with the eelworm, Ascaris lumbricoides, is one of the most common invasions of man by animal parasites. Although it is usually more frequent in childhood, it may occur at any age in the human subject. Ascaris is one of the parasites that have generally been asserted to develop in man by the direct method. No intermediate host is required. The swallowed eggs begin their transformation into the lumbricoid worm directly in the alimentary tract. A comparable roundworm is of very frequent occurrence in the intestine of the pig.
Stewart1 has attempted without success to infect pigs by feeding Ascaris eggs to them. Rats and mice, on the other hand, were readily infested by this procedure. In the course of these studies he observed that the larvae find their way into the tissues and particularly into the liver and lungs of the host. The larvae then find