PREFACE. 



In these pages I have endeavoured to bring to a focus 

 a mass of widely-scattered information, adding thereto 

 a considerable amount of new matter. 



It has been thought that a tolerably complete expo- 

 sition of the curious and intricate subject of parasitism 

 might "prove useful, not merely to professional men, 

 but also to sanitarians and others concerned in the 

 administration of public health. 



The greater part of the contents of this volume 

 originally appeared in the form of articles contributed 

 to The Field. 



I have desired that this manual should form a com- 

 panion volume to my published cc Lectures oh Practical 

 Helminthology/' delivered at the Middlesex Hospital, 

 and likewise that it should supplement my general 

 " Introduction to the Study of Helminthology/' a 

 large part of which is devoted to the entozoa of 

 Man. 



I have not here attempted to offer more than a 



