37 
ON THE LIFE HISTORY OF ASCARIS LUMBRI- 
COIDES, L. PART V. 
By F. H. STEWART, M.A., D.Sc., M.D., Major Indian Medical Service. 
(From the Lister Institute of Preventive Medicine, London, and the 
Quick Laboratory, Cambridge.) 
(With 8 Text-figs.) 
CONTENTS. 
PAGE 
I. Summary of the literature on the subject published during 1919 
and 1920 . 37 
II. The author’s experiments during 1920 ..... 39 
III. The anatomy of the larva of Ascaris suilla Duj. found on the 19th 
day after hatching in the intestine of the pig ... 40 
IV. The development of certain organs in A. suilla Duj. from the 
embryo at hatching to the larva described in Section in . 41 
V. The route taken by the larvae of A. suilla Duj. in their migration 
through the tissues of the host ...... 44 
VI. Mechanism of protection of the body against the invasion of 
A scans larvae ......... 4G 
VII. The extent of natural Ascaris infestation of pigs in England and 
treatment suggested with a view to the eradication of the 
disease.46 
I. Summary of the literature on the subject published 
DURING 1919 AND 1920. 
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, pre¬ 
liminary reports of which have already been published (1917 and 1919). 
As evidence in the problem of whether the worm can undergo full develop¬ 
ment 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 experi¬ 
mental feeding. They record five experiments on pigs which gave doubtful 
results, since the pigs fed with Ascaris eggs were found, after varying periods, 
