Since the publication of Part IV (Stewart, 1919), four papers dealing with the life-history of Ascaris lumbricoides have appeared.(1) Ransom and Foster (1920) give a full account of their work, preliminary reports of which have already been published (1917 and 1919).As evidence in the problem of whether the worm can undergo full development in one host alone, they attach great importance to two experiments, one on a kid and one on a lamb, in which after the administration of ripe eggs of A. suilla, they recovered worms from the intestines. In the kid, which died 24 days after the first feeding, the worms measured from 4·3 to 11·4 mm.; in the lamb, which was killed 103 days after feeding, the worms measured from 60 to 110 mm. The authors consider that, as Ascaris infection is uncommon in goats and sheep, the worms may without doubt be ascribed to the experimental feeding. They record five experiments on pigs which gave doubtful results, since the pigs fed with Ascaris eggs were found, after varying periods, to be on the average less infected with Ascaris than pigs which were kept as controls, and had not been so fed.
LIFE-HISTORY OF ASCARIS LUMBRICOIDES
