213 
ON THE DEVELOPMENT OF A8CARIS LUMBRI- 
COIDES LIN. AND ASGARI8 8UILLA DUJ. IN 
THE RAT AND MOUSE. 
By F. H. STEWART, M.A., D.Sc. (St And.), M.B. (Edin.), 
Captain I.M.S. 
(With Plate I and 9 Text-figures.) 
In publishing the following paper the author wishes to express 
his thanks to several gentlemen who have kindly assisted him in the 
investigation described, to Dr Johnson, Principal Civil Medical Ofiicer 
of Hong Kong, and to Dr Macfarlane, Government Bacteriologist, 
Hong Kong, for their kindness in permitting him to use the Bacterio¬ 
logical Institute of the Colony; to Dr Macfarlane for much assistance 
during the year occupied by the research, and to Mr A. Gibson, Colonial 
Veterinary Surgeon, for great help in the supply of material. 
The development of Ascaris lumbricoides is at present almost 
universally considered to be direct. It is well known that the eggs 
passed in the faeces of man undergo development in the outer world 
up to the formation of a motile vermiform embryo. The egg containing 
this embryo may readily reach the ahmentary canal of man and it is 
supposed that it there hatches and that the larva having escaped 
develops in this site into the adult. This hypothesis is based on the 
work of Davaine (1858, 1863), Grassi (1887-8), Calandruccio (1886), 
Lutz (1887-8), Epstein (1892), Jammes and Martin (1906-8), Martin 
and Wharton (1915). I have not at present access to the original papers 
of these authors with the exception of those of Jammes and Martin 
and of Wharton. Summaries sufficient for the present purpose are, 
however, available in the text books of Leuckart (1867) as regards 
Davaine, of Railliet (1895), Manson (1908), Allbutt (1909), and Castellani 
and Chalmers (1913) as regards the other writers. 
