PREFACE TO THE FIRST EDITION. 



IN this, as in the other volumes, the aim of the authors 

 is to provide a concise description of the diseases due to 

 various kinds of parasites, and of the manner in which 

 they spread, and the rationale of the preventive measures 

 advocated. 



A certain amount of systematic zoology is necessary for 

 the identification of the various parasites, but the books are 

 in no sense systematic works on Protozoology, Helmin- 

 thology, or Entomology. 



Systematic works on these important subjects will, it is 

 hoped, be written by medical men who have specially 

 studied these branches of zoology, adapted to the require- 

 ments of the medical and veterinary professions. 



The grouping of diseases according to the class of 

 parasites has in some cases disadvantages. This is 

 specially so in the intestinal disorders with dysenteric 

 symptoms. Such symptoms may be due to protozoa, 

 helminths, or bacteria. Whilst they are briefly considered 

 in connection with the class of parasite that causes them, 

 the full consideration and comparison will be made in 

 Part III, when the different forms can be contrasted. 



Major Wilkinson, unfortunately, was only able to take 

 part in the preliminary consideration of the subjects 

 treated of in this volume, owing to his absence from the 

 country, and therefore cannot be held responsible for 

 the contents of this book. 



C. W. D. 



