141 
RECENT PROGRESS IN OUR KNOWLEDGE 
OF PARASITIC WORMS. 
A PAPER READ AT THE BRITISH ASSOCIATION FOR THE 
ADVANCEMENT OF SCIENCE. ANNUAL MEETING 1912, 
SECTION D.—ZOOLOGY. 
By WILLIAM NICOLL, M.A., D.Sc., M.D. 
(Lister Institute of Preventive Medicine, London.) 
During the course of the last few years our knowledge of parasitic 
worms in all their various relations has advanced and increased to 
a very considerable and satisfactory extent. From the purely zoological 
point of view the advances have been of the highest order, many 
important discovei’ies having been made, not only in connection with 
the morphology but also, and particularly, in connection with the 
development and bionomics of these worms. At the same time there 
has been a steadily increasing improvement in our ideas of their 
classification and relationships which has resulted in a much wider 
and more accurate conception of their zoological nature. While these 
rapidly accumulating discoveries have greatly extended the knowledge 
at our disposal, they have, in addition, rendered such facts easier of study 
and of use, with the result that the economic value of the subject as 
a whole has been very materially enhanced. Helminthology shares 
with Protozoology and Entomology the, in some respects, unenviable 
distinction of being of intrinsic importance not only to medicine, but 
also to veterinary and agricultural science. It has a smaller but no less 
definite economic importance in relation to fisheries. Apart from their 
purely zoological interest it is particularly as agents of disease that the 
parasitic worms are of importance, but there are a number of other 
matters connected with habits and distribution, on which a study of 
parasites may throw considerable light. 
